It all depends on what brand of roller you get. The ezrun 150 amp is HUGE!!! Won't fit in some rollers because its too big. I'm running the xerun 150 amp and it has plenty of power on 4s. I did have to cut the mud guard on my tekno to get it to fit but the tekno chassis is extremely narrow compared to most cars on the market. I only run a mamba max once from a friend. Heard they have problems with the internal bec failing.