I have a HopNot kit on my 2013 Challenger 6 speed. It definitely helps with hop on the road and a little bit on the track. I have all season tires so the kit may work better with summer tires. On the road, under dry conditions, the car hops a little with a moderate launch around 1600-2000 rpm then grips and runs. In the wet it keeps hopping. On the track you still need a gentle launch either at low rpm or riding out the clutch as I did before I put the kit on. Overall the product has some benefits and is probably a good starting point for improving hopping, not a cure. However, my biggest complaint is I wanted to take it off as I would like to trade the car for a new Challenger and it certainly does not help trade-in. I have tried several times to get the "back to stock" inserts that are sold by HopNot and been told they are not in stock as no one orders them. Of course if no one ordered them they should be in stock. I am beginning to think these do not really exist and they are on the site only to sell the kits with the false impression that it can be easily removed.