Great thread...
I'd like to add one more tip:
The original sprint 1 had a much nicer steering assembly. On that one the left side is sandwiched between the chassis and top deck (the pivot post where it rotates runs all the way from chassis to top deck, holding the assembly firmly) so it does not have the problem the sprint 2 assembly has (because sprint2 bearing has no support other than the lower chassis, with no upper support). You can still get them new on ebay. A few months ago they were on towerhobbies too, but it's no longer the case.
Part # is HPI 86005
http://www3.towerhobbies.com/cgi-bin...?&I=LXDHR8&P=7
here's the steering assembly exploded view for the sprint1 in case you're wondering, and a picture of that chassis. You can see how it fits in there. Part is a direct fit to the sprint2 chassis. In fact, sprint 2 uses a lot of the sprint 1 parts.
cheers all