I have had many discussions with my clutch builder about clutches and all that. First, he says that the number of buttons on the disk deosnt really effect the holding power of the clutch, but rather the ease of using the clutch. You would think otherwise, but its just not true that the more buttons on the disk, the more holding power. Second, clutchmasters and Spec use the same exact pressure plate, most likely a LUK. From what I know, both use re-worked versions of the LUK, to give a greater clamp load. Both companies claim to have a greater clamp load over stock, but how much, is not known exactly unless it is tested in a plate load tester. The only things you can do for a stronger clutch is to increase the clamp load(but there is a limit), the TYPE of friction material(the coeficient of friction on ceramic is almost the best you can get), and increase the overall diameter of the clutch disk(can only go a tad bit larger than stock). If a clutch masters stage 4 isnt doing it for you, then the Spec wont be much better. Both are about the same thing really. The problem with upping the plate load pressure is one, it puts a lot of presure on the engine bearins, and two, if the load is too much, you run the risk of the clutch not disengaging. I read in HRC's post of him in the 10's, that he had a dual disk clutch made for him. If you can get hold of Bill, maybe he can let you in on what he uses. It seems odd that your clutches are only lasting 20 or 30 thousand miles though? You are using ceramic facings on your clutch, and those should last a looog time. You will actually wear into the flywheel and pressure plate surfaces before you wear down the facings. The ceramic is a very hard material.