I have two 86 220's and two post 89 250's and have driven a massive amount of customers cars over the years, both modified and unmodified.
I personally prefer a well sorted 86 car, both in the looks department, and the performance department.
As Pete mentioned, the 220 is a lighter weight car, no anti lock brakes, unlikely to have an LSD, and should have the original smaller turbo, which are all points that I prefer to be honest, as it makes the car in standard form more nimble, less laggy, more engaging, more progressive / more forgiving close to the limit.
My personal findings with the 86 220s are..* They are less laggy due to the smaller turbo.
* They are a little more nimble due to the weight (but also there are suspension geometry considerations to the feel of the early offset cars)
* They are more engaging to drive because you can't rely on the ABS.
* When they let go of the rear end when used in anger, the lack of a LSD means they tend to be less snappy and easier to recover/control on the limit.
* On a track the only bit that I am not as keen on would be the brakes, any of the cars without the M030 front brakes are easier to overheat and can be a little more snatchy.
However, the later 250 cars, more often than not are UK SE spec cars, which benefit from sports seats, often have M030 suspension (but not all) and more often than not have the bigger front brakes.
I prefer the look of the early offset teledials on a 944 turbo.. but that is a personal thing, I just wish they had made the teledials in 7.5J and 9J as with the 89 onwards turbos usually wear as design 90's, but having said that, it may have reduced some of the forgiving and engaging nature that I love them for.
Either car with a chip and some minor wastegate trickery become a much improved beast with less lag, more torque and more peak bhp, but without any real drawbacks such as reliability issues.
It used to be that a 89 onwards SE spec car was what everyone, including me, advised someone buys, partly because of all the included optional extras such as M030 brakes and suspension, sports seats.. Back in the day my favourite personal car was a 91 Black turbo SE with CUP1 wheels, 968 wing mirrors and door handles, just as everyone back then seemed to go for and the 86 Turbo was seen as the poor relative.. But as time has moved on, the 86 now (in my eyes) looks really retro cool with the teledial deep dish wheels and from a drivers point of view has a personality that I prefer.
As the early offset 220 cars (they did of course make late offset 220 cars through to the 88 models) were often seen as the poor cousins, they were sometimes less desirable, and therefore were not only made for just the one year or so, but also were more likely to get the chop and end up in the bin when something major went wrong, which now makes the 86 944 Turbo a bit of a rare car in the grand scheme, which also has a bit of a following for the same reasons as I like them, which does mean they can command some decent price tags.
In order of value, I would probably say they sit in this order..
1 - Turbo Cup cars (I have one which is a restoration project) which are super rare.
2 - Turbo S (I might get flamed, but.. most of them are the silver rose cars, which have unfortunate exterior and interiors for the eyes) which are quite rare
3 - Aug 85 to July 86 Turbo's - (early offset non ABS lighweight 220 cars) Getting thin on the ground to find a good one, or one at all.
4 - 89 onwards Turbo SE models
5 - Late offset 220 cars built from Aug 87 onwards
But it is absolutely down to condition, service history (and paperwork) condition and condition... I know I mentioned condition many times, but these days it should be probably the number one consideration from an owners point of view...
Mileage is an issue, especially for collectors. Typically, a collector will not touch anything with over 100,000 miles, sometimes half that amount... But with very few like that, collectors are buying ones with up to 100k on the clock. However, most of the super low mileage ones I have seen have seemed to be in great condition, but if they were ever used, they would become a nightmare of every rubber component falling apart (hoses, mounts, bushes, seals, bushes) which on a higher mileage car would almost certainly have been replaced during the cars life.
Now the last thing, bubbles.....
I was in the Porsche world in the late 80's and early 90's when the classic car world went crazy, values went up, people were even doubling their money on deposits on new supercars by selling their deposit to people who were impatient or speculating in value increases... I watched mad things like Jag E-Types go from being £5k cars to being £120,000 cars over night (which were the extreme of the market) and cars like 911's double in value... I was also around when the bubble burst, which had those e-types worth less than £10k with receipts for £80k restorations in the last year, which happened a couple of years into the 1990's...
There is a very significant difference this time round.
Back in the late 80's and early 90's the problem was that following a depression, house prices shot up, gold shot up, everything went mad, people thought they had money to burn, investments leveled out and the classic car market was jumped on and values soared... The cars remained in the UK.. interest rates went through the roof to control inflation, many people found themselves skint, house prices, the stock market and classic cars suffered and goverments learned a big lesson in trying to put the brakes on too hard with interest rates.
This time, no matter what happens, the big difference is many of the 911's and 944's which have shot up in value have buggered off... Emerging markets which did not have the "Yuppies" of the 80's buying flash Porsches new, now want them and want them badly. So right hand drive markets such as Australia and NZ , Singapore, Hong Kong, China and many other far eastern countries... Even if the interest rates rise, investments start doing better, or Brexit causes more financial distress, which at the moment if anything will help continue the rises, these cars are not magically going to reappear in the UK market as they did during the early 1990's bubble popping episode.. Those cars are gone and will remain forever rarer in the UK because of it.
Not only this but something else has been happening in the world of car enthusiasts other than rising values causing investment opportunities, the 911 has come of age and appreciation... But more importantly for the 944 market, so has the 944... There was a time, like the Ferrari Dino, where people used to look down on 944's.. Anyone who had one 20 years ago would certainly of heard digs along the lines of "Isnt that one of those poor mans Porsche??" or "Isnt that one of the ones with the Audi engine?".. Some of that should have been directed at the 924, but not really with merit, normally just with envy, but it used to happen.. the 944, and in particular the 944 turbo used to be the unsung hero and best kept secret in the Porsche world. Rarely today do you hear people coming out with those jibes, now more often that not people comment on "Is that really a 1986 car??" or "Wow you don't see many of them anymore" or "Didnt Jeremy Clarkson and Tiff once own one of those and say they were one of the best cars they ever owned?"
Sorry if any of this offends anyone.. It is just a realistic interpretation of the market from what I see as a Porsche specialist that sees a massive amount of these cars on a day to day basis, many of those being cars that the people have just purchased, have in collections, or are trying to sell.
I have been predicting a big shift in prices of the 944's for many years, you can probably find me talking about it in the archives here going back years.. It is happening and they have not peaked yet, far from it.
Take note, I might own 4 944 turbos, I might also own a 944 Lux, an S2 Cab and a 944 S2 Coupe and a rare 944 turbo cup (in many parts).. But none of them are for sale and I have no axe to grind, to be honest, the market would have to go up quite a lot for me to part with my favourite ones as they are part of the family now, the only thing the change in market makes likely for my 944 collection, is that I can now justify spending even more money on them! lol
I agree with Stuart, buy the car that's in the best condition, if it's been used daily or near as then don't worry about the mileage, it's irrelevant as long as the car has a good list of receipts to show that it's been cared for during those miles . If it's been standing for any length of time then you need to be wary and take extra care when viewing, these cars hate sitting idle...IMHO a low milage car ( I mean much lower than the two that you have stated which for the year are fairly low) are only good for sticking in the garage as an asset, soon as you use them on a regular basis the bills will start mounting.
