something also to take note is the hardness of the rims and the flex each brand provides.... My personal experince at this one trackwhich is a smaller low to med bite track i race at is that i ran back to back also with the same prep and rutine as i do and making sure the width is the same between jaco/parm and crc tires i was instantly .2 to 3 tenth slower a lap with crc and the car felt i dunno hard to explain like it was still fast but "ontop of the carpet" compared to jac/parma but like i said it is just at this one track im thinking cause gthe track is smaller the flex and give of the jaco/parma gives it that little bit of extra i needed...
But on other tracks dont have a prob....
Def like the way the front bearings firin the crc though..