i think one of the problems is that people think they can get solid roller performance from a hydraulic roller. a hydraulic tappet, roller or flat, can only be accelerated so fast. the faster the hydraulic tappet is accelerated the quicker it fails. i've looked at advertised profiles from comp cams, engle and crane and have never seen anything that impressive for the extra $1000. i can buy a lot of ZDDP for a $1000. the hydraulic roller retro-fit stuff is just another pit to throw money in. if you want roller performance, then buy a solid roller.