Think keys, ideally you should have two bright red keys, check that they open the doors by remote...also check to make sure you do have that dark red master key. Loosing these can cost you big time.
Check Air/con, make sure it gets cold
Check how it idles
Check how she drives fast, 80/90 mph etc (145 mph is fun wink )
I bought mine and the factory fitted cd player jumped and skipped around...so i replaced mine. (Ripped out all the cables and started again, dody italian cabling!)
Do the obvious stuff too, check oil patch under the parking spot (ask where the car is usually parked!), check for signs of wear and tear suggesting a different mileage, check panels all spaced out nicely, get AA in if u need too.
And then get the car straight over to Acton, London and get autodelta to change the suspension, slap a chip in there etc...she'll be lots of fun and you'll be surpeised the roar she gives out with an airfilter and sports exhaust (remove the cat too wink )