Thought I would provide my perspective on C4 ownership so far -
Ive owned my 89 C4 for almost 8 years. I was fortunate in that the previous owners took great care of this car and it had all regular scheduled service and service records back to the very first oil change at 5k miles.
My C4 currently has 168k miles on a virgin motor and AWD system. It has a minor weeping of motor oil but nothing I worry about. There are no previous repairs to the AWD system other than normal maintenance and checks. I just had the entire brake/hydraulic system flushed and all is working just fine. Its true the AWD system is a complex mechanical setup that most likely will be costly when something goes wrong but so far so good. I have spent more on the A/C over the last 3-4 years than anything else.
As for the handling of the C4 - it definitely feels a bit heavier than a C2 and the inherent understeer can be eliminated with suspension tuning. There is also a bit of finesse and technique to driving the 964 C4. Search the web for a series of articles titled "Wringing out the Carrera 4".
I've had the car on the track at Auto Club Speedway and Laguna Seca, several AutoX events (Won my class several times) and all over the SoCal mountains and although I dont "need" a C4 Ive learned how to drive this car the way it was intended and is a nothing short of fun.
Love my C4 - Good luck with your search.
