I've owned my '90 Sigma for about seven years or so and I've been extremely happy with the car, save for the high cost of parts (although, maintenance is a rare thing, as most of the parts last a long, long time.) The interior is, by far, roomier than any comparable 4-door I've ever been in. The exterior is distinctive without being gaudy. The engine, with 173,000 miles on it, runs just as good as it did 20,000 miles ago. The only issue I'm having at the moment (besides the need for body repair) is the transmission, which is starting to slip. Past that, this is an absolutely wonderful car. On a side note: the reason parts are so expensive is because it was a limited production car for the US. :)
Everything, really. I love the in-steering wheel stereo controls, all other controls readily accesible, plush interior, great handling, superb supension... It even has a little cubby built into the drop down arm rest for the back seat and felt covered plastic (you know, the plastic between the windows?) Plush!
About the only improvement for the Sigma that I would have suggested would be to perhaps advertise it more when it was first introduced in the US. As I said above, it's a relatively rare car, which makes getting parts difficult and expensive. But, if you know basic auto repair, you can save on labor.
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