Ok so i took out the heavy pivot post and the car runs AWESOME !!! on our track which id describe as medium grip bumpy ashphalt, and my ususal tamiya medium rears with tamiya hard front rubber tyres the car was awesome. I ususally do 22 second laps with the odd 21 second lap. Today i did consistent 21 seoncd laps with a few high 20 second laps in there as well...
I think the rolling damper adds some predictability to the car which allows you to improve your consistency.