I have tried GRP tires with very good result but since a year a go i`m using Enneti with very good result. This is not a GRP brand, is a new factory with new owner since a couple of years. In touring car the last series with harder rims are very good. They have like a skin in the sidewall to prevent any chunk when you hit. The perfirmance is similar to any GRP tire with a little bit more steering. From my point of view and my driving style is the way to go. In 1/8 they are excellent. Top team drivers from many manufacturers are using this tires. For example, this are the tires that the Mugen France Team (JP Racing Team) is using