Quick Question

i have a 2004 2wd gmc sierra and i want to put some billets on it. my question is what backspacing and offset do you think im gonna need

cool i guess no one owns one or at least put rims on one

It depends how much of a lip you want, also are you planning on narrowing your rear?  Most NBS we would do a 22x8.5 w/ 6" to 6.5" bs for the front, and a 22x10 with a 7.25" to 7.5" bs. I sell Intro billets if you're interested.