You mean these? [
]
I am doing this mod just now and can offer my findings..
It is called a badge panel.
The vents are no longer available from Porsche.
They are no longer available from AutoAtlanta.com despite being listed on the website. Link here..
http://www.autoatlanta.com/Porsche-Grille-Insert-924-Turbo-Four-Req-Parts-PN-B477853381.html
A 931 badge panel is very hard item to find...
..and if you thought that was hard to find, vents are harder.
The 931 badge panel does not fit the 951, the shape is completely different.
The 931 badge panel is spot welded onto the car- which means if you find one, it'll have been drilled/cut/torn off the car.
The 951 badge panel is bolt on for easy on/off'age.
The 951 badge panel has a structure on the rear of where the vents will sit effectively blocking them off and rendering the vents useless - this renders the argument about any impact on performance as boll-ocks.
There are two ways of doing this mod..easy way and hard way:
Easy way- cut a section with the four vents out a 931 panel and graft them into a 951 panel.
Hard way- cut four holes out a 951 panel.
There is company in Germany do a fibreglass panel for a 951 with the four vents holes, it is on their website as out of stock. They actually can supply the panel but have removed it from sale because there are no vents available. If you can find vents, you can buy a panel as they will fit. Here is a link to the panel..
http://teilecar.com/?1341,frontblech-front-panel-gfk-grp-porsche-944-s2-turbo-951
I would not put a fibreglass panel on my car.
If you search ebay.de for "Porsche 924 turbo Lüftungsgitter" you may find some vents in Germany. This is how I got mine. I do not know the French, Italian, Spanish translations..but don't limit your search to the UK, ebay spans every country the 931 was sold in!!
My vents are costing me £95
My 931 badge panel was £125
I bought a 951 badge panel for £68
I suspect my bodyshop will charge £150 for labour..
..and another £150 for painting and fitting.
That's almost £600 for this mod.
There is a work in progress thread all about it with pictures here...
http://www.porscheclubgbforum.com/tm.asp?m=848201
There are some vents on ebay.de right now, but I think you will have to buy the whole front of the car to get them! I doubt the seller will split..
Only 500euro + shipping..[
]
http://www.ebay.de/itm/Porsche-924-...543169211?pt=DE_Autoteile&hash=item3395007cbb
You now know everything I do.. that was a short summary of many many hours of research you got there!