Rusty exhaust.
Replaced both CV joints since I've had the car.
This is probably one of the most reliable cars that me or anyone I know has ever owned. Pretty quick considering it's only a 4, and it's a lot of fun to drive when you really get the engine wound up. One of the more surprising things about it is how well of a highway driver it is, with the exception that it can get a little noisy when you pass other vehicles. The other great thing about it is that it's supported fairly well by after-market performance parts makers, and it's pretty easy to add a lot more horsepower to them.
I also have a '90 Integra. I love it! It is fast, durable, fun, reliable, and gets great gas milage. What else can you ask from a car? The only thing that I recommend is that you MUST keep up on all your maintenance. If you do that your Integra should last easily 200,000 miles.
I have a 1991 with 70,000 original miles. I tried selling it this year, but no takers so it looks like it will be my summer car. I agree about the durability of these things. Look at some of the mileages on the Cars. com site.
I have a 1991 Acura Integra wonderful little car I am 18 and its my first tuner car you can't ask for a better one it has over 180,000 miles and the engine sounds like it just came off the show room floor as long as you keep up with the maintenance they truly are a reliably car every time I get in it I feel very confident that I will get were I am going around town or out of state I give the little car 2 thumbs up.