Well the Xrs is a totally different animal. Verdict is still out on the longevity of this high compression engine. However, it is a Toyota (although the engine is a joint effort with Yamaha). I generally a conservative car purchaser and I had total confidence in buying the Xrs. I haven't regretted it one bit. In fact I didn't realize how much I was going to enjoy this car. You can't beat it for fun factor with 'Lift'. The aftermarket stuff is decent for a Toyota. More there than I'll ever want.
As for known problems:
1. Clutch is very notchy and there's been a high rate of premature failure on the early models.
2. Belt squeel is another problem. Various culprits from belt tensioner to A/C pulley tp alternator pulley. Most have been within the normal warranty period.
3. Fitment of body panels (rear bumper!) is definately the GM portion of the build.
Overall, you won't be dissappointed. As for the extended warranty, I didn't go for it but others have, it's a gamble. Good luck with your decision and let us know what colour you get!