Whatever works for you. I've done both 1/12th and 1/10th I only use the CRC springs. you'll have to experiment with the tire sauce as I don't let it sit long before I wipe it off. Also experimenting with different bodys to see what works for me. For foam I like the HPI Porsche GT1 and the rubber the HPI C6 Vette. I've tired the protoform PF10 and Camaro Z28. I like the Z28 on Foam and waiting to try the PF10 on the new chassis. I did not like it before on either car. Have a Nissan Silva to try on Rubber. I won't have any results for a couple of weeks- till I return.