Im not sure which battery you are running but i seem to like a heavier pack on a looser track surface. You did go down a spring rate so thats a good thing. Maybe leave the same set-up and springs you run on the high grip track and try a full size pack like the reedy 5500 60c i believe it is, they weight about 306 grams. I was running one without the rear ballast weight just weight in the rear triangles and battery forward and it was really good with white rear spring and gree nfront spring and same oil and pistons. I would also try the A hubs if you dont already have them on and 2mm on the inner ball studs front and rear and maybe 3.5 toe block. Im not saying the heavy pack is the answer but if you have one laying around give it a shot. Just this last race day i tried what most of the team guys are running in practice and liked it since i came to the track with a slightly different set-up on my car and didnt end up running my current "heavy car set-up" but think im gonna go back to it for my local track.
Eli, how do you like the Exotek hubs? Good bearing and hinge pin fit? What about BB clearance?