At the risk of this starting to turn into a dogpile, the kitbot drivetrain was really intended to be used with 4 CIM's. I've forgotten what the targeted final speed for the Kitbot is, but I think it's something like 10fps. Take a look at
http://team358.org/files/mechanical/...nRefTables.jpg
With two CIM's and the KOP wheels (~1.0 COF) you're in a very marginal area of the chart for normal driving and almost certainly current limited in a pushing match. It's just geared way too fast. With a full weight robot you may have trouble even turning on carpet.
The kit bot with 4 cims is going to give you way better performance during normal drive (better acceleration, turning and happier motors). It's a pretty easy upgrade to make in the pits and totally worth the weight and controllers. If, for whatever reason, you can't add in the extra motors, strongly consider things you can do to ease turning and/or limit traction. Things like swapping traction wheels for 'omnis' or programmed acceleration curves may help with drive performance, and coaching drivers to resist the urge to push is just about mandatory here.