When I first purchased this car it ran great. Currently have about 90,000 miles on it and I am about done throwing money into this thing. I have some of the same complaints as others; wind noise, not a very smooth ride, and most of all expensive to fix repairs. Inside door handle broke, I can only get from the factory they want over $200 for a piece of plastic. Back end has begun to sway. I have had over $600 put into it plus new tires and problem still isn't fixed. Probably going to need new shocks soon, most likely will get rid of it by then.
Really liked the car when I purchased it with only 24,000 miles in 2004. By the time it had 40k miles it had the very common heater core leak... by the time it had 50k miles rear/driver side abs speed sensor failed so abs brakes are non-functional since then, neither is the traction control... both ABS and TCL light stay on all the time now. By 55k egr solenoid failed, not too costly to replace if you do it yourself. By 60k miles the rear springs are worn out, with 3 passengers in the rear the rear bottoms out, replaced shocks which didn't help at all. By 80k antenna motor failed. Bottom line, even though I like the car I wouldn't buy a Mitsubishi again, with the other options.
I purchased a brand new 2001 Diamante LS and have had zero problems with this car. I have driven it everyday (city+highway) and the quality has been simply outstanding... Tires-Oil-Gas only. Mitsubishi built this great car to last many years.
Extremely fun car to drive. Plenty of power for those short straightaway passes on secondary roads. I have found that the gas economy is excellent. I average about 25 mpg on the highway. The seats are extremely comfortable and long term driving is virtually effortless.