The general AT2's are a great tire. As far as back spacing I left that up to my tire guy. For your rims, you could Plasti dip your stockers for now to get an idea of what it might look like. Bully dog is the best pocket programmer and should suit your needs. Unless you have plans on adding headers and high flow B pipes. Then you will need Uprev. For exhaust it depends on the sound you want. Magnaflow, Banks, and the new Gibson Metal Mulisha are popular choices. I can vouch first hand that the Banks has quie a bit of drone.
'07 CC 4X4
banks ram air w/ tb screen removed, banks monster exhaust, prg minilift, PRG UCA's, PRG endlinks, 5100's all around, DK shackles, Brake motive brakes, headlight mod w/ JB switcbacks, Legit 55w 6000 hid's (lows and highs), modded tail lights, street scene grille shell, xd diesel 20x10 w/ terra grapplers, pinch weld mod, axle vent mod, BW pocket flares, PD'd stuff, BL step rails, SM designs bezel kit