Don't waste your money on new spark plugs yet. Wait until you have had the car running and decided it is worth saving. Providing they are clean and reasonably gapped, expect them to work. Sitting idle for 5 years has no effect on plugs, it is usage that wears them out.
Clutch.
"Clutch will have a good chance of being seized. Sometimes they can be freed off by towing it , other times it is a strip down job."
No need to strip down as Mr Porsche provides a useful access plate in bottom of bellhousing.
Sit in car, press clutch to floor, measure distance from pedal pad to back of lower rim of steering wheel. Cut a piece of wood to this length and prop clutch down so that the spring load is off the centre plate.
Jack up nearside and place axle stands under front and rear for safety.
Find a comfy carpet offcut to lie on and slide under car equipped with a Phillips screwdriver and a thin bladed table knife. Plus a torch or lead light.
With the plate unscrewed and removed, you can see the flywheel cover bolted to the flywheel and at regular intervals there are opening/slots that allow the dust to emerge. You will also see the edge of the friction plate. Carefully insert the blade between the flywheel and the plate, then between the cover and the plate. No need to get vicious and chip bits off, just gently ease the blade in about a quarter of an inch. Usually very little pressure is needed to unstick the surfaces but if necessary turn the engine using a socket on the crank pulley nut. Bring the next 'access gap' in the clutch cover into view and you then repeat the 'easing' bit with the knife blade. On my car (static for 4 or 5 years) it took just one attempt through the very first 'access gap' to unstick the plate.
Usage will then clear the very slight rust marks that are usually left on the surfaces of the flywheel and cover plate.
Above is a lot easier than dragging the engine or transaxle out - and it works.
Tyres.
If tyres have been flat they will probably have developed cracks and be totally unsafe to use.
Brakes.
Outdoor storage means you will probably find enough surface rust on discs to prevent easy movement. So that means wheels off and clean up surface with emery cloth or similar. I would remove pads and ease piston back into caliper to ensure it was not stuck. Check caliper slides are clear of rust and clag.
If handbrake was left on then rears are probably stuck also. There is a bung in the backplate (NOT the two outer plugs to allow you to check lining thickness) that you poke a small screwdriver into in order to 'de-adjust' the brake shoes. Having done that, thump the drum a few times with a rubber or plastic faced hammer and they should free up.
I wouldn't worry about oil and the top-end. If, with fresh petrol, the car starts even for just a few seconds on the cold-start injector you should see oil pressure gauge instantly rise and any wear due to lack of oil would be so low as to be impossible to measure in real terms. Only if you were cranking it over for ages with no pressure at all would you run into the slight risk of scuffing valve stems, cams or bores.
]
