noone that i know of other then proclutch.com uses stronger pressureplates for the 420a noones progressed a need for it advanced materials over come the need for high clamp loads...
You can have it cheap, fast or good. Pick any two.
If you want it cheap and fast, it's not going to be good. If you want it cheap and good, it's not going to be fast. If you want it good and fast, it's not going to be cheap.