Those vulnerable wings, bonnet and bumpers are glassfibre, so look for cracking, star-crazing and signs of past repairs.
Most of the rest of the car is made from thin 1980s steel so go over it all thoroughly to check for rust issues and repair patches.
Panels gaps were never Porsche standard, but look for any misalignment that might be the result of past accident damage.
The engine continued (detuned) in the GT Turbo, so parts supply is surprisingly good and reasonably priced.
Head gaskets blow so check filler cap and dipstick for signs of oil and water mixing. A cold start will reveal an ailing turbo’s puff of smoke.