Well (given that I have only driven from the garage to Cadwell and back to W Yorks) in day-to-day use they don't seem any different. Pads would make more of a difference, but I think the grooved discs may be better at stopping the pads from overheating, as we were using what appeared to be standard "Renault Brembo" pads, which didn't fade at all. They were maybe a touch keener once warm, but weren't bad when cold.
The main benefit seems to be that I am not too concerned about them warping being as they are a two piece design - I have warped two many single casting discs, and it gets annoying.
The main benefit seems to be that I am not too concerned about them warping being as they are a two piece design - I have warped two many single casting discs, and it gets annoying.