I have 2. One is hooked up into r1 and shoots 11.5 shots per second for cod 5 and 25ish for cod 4.
My other is button on the underneath that you use instead of r1, but isn't as fast as the other. Not played with it yet.
There is alota sights out there it depends on what quality and what you want the usual price for a modded controller (either system) is around $110 and thats for controllers that have been modded and (better) last awhile im sure theres alternitives out there OR you can just spend for bucks for a finger trainer XD!