Clutch Assembly

Does anyone know if there is an aftermarket clutch available for 04 Silverado's? I just replaced mine in my Truck, which only has 33000 miles on it. . Granted i changed out the 5speed for a t56 6 speed, and LS7 clutch assembly when my truck had 25000 miles on it. That said, i'm sure my clutch assembly will break again, so do you know if there's a company that makes a more stout one.
On my truck, the plastic piece that holds the master cylinder in the firewall broke. . I replaced it no problem, but would like a real fix instead of just stock which i'm sure will only last a little while. I'll post some pics later so you have a better idea of what i'm talking about if you don't already

i whent with a spec stage 4 on mine

the only crapy part is is sucks if your in heavy traffic you can feather it a little but its mostly all or nothing

this is spec web sight

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How come you can feather it? is the leverage point different or something?