Smaller pulley will get you some, but doing a flex fuel mod and a tune to run E85 will get you a lot more, but then you would have to upgrade your fuel pump and go with bigger injectors, or you could just do the pulley and meth injection to cool down the IAT's and a dyno tune for that, and get some good gains. From what I have read on this forum. Look through this section, and ask.
https://www.camaro5.com/forums/forumdisplay.php?f=74