I've been using the stock hyper 7 carbon shoes on my car for two years now and more than 7 gallons and do show some wear but NOT much.
I have also noticed that the holes on the shoes tend to get bigger every time I take them off for cleaning but it's much better than the teflon shoes (white)
I haven't used alloy yet cause of the maintenance they need every race or so...!

Anyone knows what kind of springs are available for three shoe clutch?
I do know of the 0.9, 1.0 and 1.1 but wondering whether we have more options or if some are better than others?