ttr, Congratulations on your purchase of the XXX-S! It's a sweet car, and I'm sure you'll love it. I just built mine a month ago and didn't have any problems what so ever. Just take your time and pay attention to the details. It's pretty straight-forward.
Here's a link to a site that has lots of information on the xxx-s. This guy also visits this thread often. Check it out.
http://www.fictionlab.com/losifaq/index.htm
Jits
EDIT! Forgot to mention one thing! In the steering assembly, there are 4 5mm bushings that come with the kit. Go to your LHS and get 4 5mm bearings and replacd those right off the bat. None of us really understand why they put bushings in the steering assembly like that. Ok, that should cover it.
Jits