Anyone using the MRL solid roller lifters?

Big block or small block? What kind of spring pressures?

I am looking at a set of the Pro sports for my sb since they are supposed to be a direct drop in (i.e. no grinding on the block for clearance) and feature pressure fed oiling to the rollers and needles.

Just wondering if anyone is using them in either a race or street application (mine is both street/strip) and how well they are holding up. They seem like a quality piece, but I'd like to see some reviews on them before I pull the trigger