Everyone should know by now what a sleeper of a car this is. The power was awesome, the elongated leather seats were the best on my back although some extra side of seat firmness would have helped. The engine was flawless until about 90k when the supercharger pully bearing started to fail...otherwise, it was perfectly reliable. The only complaint is that the front-end was a little long and tended to scrape on declining-to- street entries. Mine is gone now - the victim of a side impact directly on the B-pillar from a Dodge 2500 truck. I miss the car but most importantly, it was built well enough to save my girlfriend's life. Easily, best in its class - it was just never properly promoted.
Supercharged Engine, Seats (mostly), factory stereo sounded great, Ample truck space, the surprised look on people's faces when they love the car and find out it's the old fogey stigmatized Buick!
(7 years late :) - Shorten front wheel to nose length, selectable ride control (firm setting needed to match the engine sometimes), firm up the sides of the front seats, find marketing niche in between Camry and 530i and promote to "quality/reliabilty mainstream buyers" - it's a winner!