I had a lowrider, twin cam 95c.i. 251 cams, se lifters, cnc ported heads, upgraded springs, roller rocker, I forget all the upgrades, but after the $6500 in performance upgrades the engine grenaded when a SE lifter cracked and spilled little cam bearings into the engine at 30,000 miles. The R3 is designed for the power and won't require the rebuilds a harley will.