Transmission, water pump, sunroof bracket.
A bargain for the performance. This sedan will outperform most luxury sports-sedans even if they are ten years newer. The engine is bullet-proof. The trannie will start to go out at about 110,000 but most likely it will only be the overdrive. It will be driveable for a good twenty more, however I don't recommend this. Drive it for as long as it takes to repair it and spend the $2800 at AAMCO. They'll warrantee it for the lifetime of the car and the engine will go and go and go.
I've owned my 1991 Q45 for about 7 years and will say w/out question that it has been a fantastic car to own. Repairs at the Infinity Dealership have been expensive but are *well* worth the value you get back in terms of service & warranty. My next car will be another Q45 in about another 60 - 80k miles!
- Curtis.