Generally, the best way to avoid/cure creep is to crank up the boost.
The only way I found to truely eliminate creep is to swap to a 34mm flapper, or go to an external w/g. Though, going to the 34mm sucks because it can cause you to be top-limited on boost once the pressure pre-turbo in the exhaust system gets high enough (you'll have this problem on a standard-size WG as well, but the larger flapper makes it worse).
O, cranking down the internal wastegate to help boost response has nothing to do with creep.
Shane, while enabling the flapper to open 90* seems as though it would help, remember that the wastegate actuator is what actually controls the movement of the flapper, and the w/g actuator doesn't usually have enough movement in it to open the WG much more than that original 30-45* anyway. You could try changing the length of the arm (as I know at least one person on here has) however, that comes with its own set of problems and doesn't seem to resolve it all that well anyway. Turbo companies go to great lengths to figure out what works best, so unless you're doing something really nutty, most changes like that will net little to no benefit.
Porting of the o2 housing (w/g portion) may help a little bit, but I wouldn't expect it to resolve it totally. Externally dumped o2 housings don't tend to help much either and sometimes even worsen the problem -- the same with removing the cat/exhaust (as you found out/experienced).
Or (the best solution IMO) just get a bigger turbo.
). I hope to see everyone 
