If you can't find anything tweaked, all your springs are the same length right to left, the shocks are the same length, your droop is even, and your spring preload is even left to right, it's probably a weight balance issue.
What battery are you using?
The car is balanced alright with NiMH batteries, but still a little light on the battery side. If you're running a LiPo, it will be extremely light on the right side and will either traction roll in a right hand turn, or not turn at all turning right.
There's two small balance holes in the chassis at the center line just behind the center front bumper mount screw, and just forward of the rear bumper mount screw. Find something suitable to set the car on at those spots [I made some balance tools identical to the ones hudy makes], balance the car and turn loose. Whichever side falls is the heavy side. If the car stays balanced, you're good.
I can take pictures to demonstrate if it will help.