The first 626 was a rear wheel drive car with a little 80 horsepower engine. It actually had decent performance overall, although it was never a car that you'd take to the track. It was compared by many reviewers of the time to the BMW.
The first front wheel drive models of this car appeared in 1983 when it was changed over to the GC platform. It had better performance numbers and was awarded car of the year by many car magazines. Some markets got an optional twin carb engine making over 100 horsepower, but not the U.S.
1988 saw the introduction of the Mark 3 version of the 626, based off the GD platform. The base model was now up to 110 horsepower with a turbo model making 145. Some people think that number was understated by a good 40 horsepower due to performance numbers comparable to cars with supposedly much more powerful engines.
The GE platform used in 1993 for the Mark 4 was a big change for the car, with completely different styling and a smoother look. The turbocharged model was now a true large sports car, with 187 horsepower from a V6 engine.
The 1998 Mach 5 was considered a downgrade by many reviewers. The car became less powerful as the ride was made smoother. It was an appeal to the luxury market, but at the expense of the sports car market.
These cars can be found quite readily on the used car market. You'll find them listed on eBay for lower than average prices, and you can also get some cheap parts there.