Don't worry Johnny tells me that every time he sees me, which is a few times a week!
I had a Southbend Stage 3 Endurance full face sprung DXD and the pedal was slightly stiffer than OEM but it still had smooth and quiet engagement making it easy to drive daily. However, it started slipping eventually when I was at 560whp/525wtq. I believe they are good to 500wtq so it should hold for you, but if you plan to go higher than I would recommend getting an upgraded pressure plate. Also, don't forget to get a lighter billet flywheel along with it.
Currently, I am on a Southbend Stage 3 Drag (6 puck) with upgraded pressure plate. I was told it should hold 800+ wtq and am currently at 678wtq. It has been holding quite well, but is a heavier and kind of twitchy. Even with the RJM pedal there is a grabbiness to it that makes it slightly cumbersome in daily stop and go driving. I am told it isn't as bad as a Clutchmasters, but there are still some nuances that take some getting used to.