Your fuel system is the best one GM offers. It has more capacity than ZL-1. As I'm sure you've checked, your friends at Squash can help you gain more if needed.Another great source is Greg at Pace Performance. He personally has a GXP stick with a 2300 Magnacharger and lots of fuel mods etc. Very well versed in this GM supercharged CTS-V (and other GM vehicles with stock SC). From what I understand it is basically a 1900, with rear air inlet.
Isn't it nice how much easier it is to switch ECM's in GM cars! Are you going to ask original owner about who tuned vehicle? Would be worth it to have 2 ECM's. That way, you could have 2 tunes ready, if you decide to run E-10, or have to. I am able to switch out ECM's in my G8's in a minute.
Does it have a custom CAI?
As for wheels, how about a wheel spacer that moves the wheel out an inch or whatever you need to clear rear brakes? You can even get them with changed bolt patterns so you could run Ford bolt pattern on your 120 mm pattern Caddy. Smaller diameter tire like the 17's you had may not have clearance issues with fender, especially if you can firm up rear so it squats less. I run 17x9.5" Borbets on my 09'G8 with 275 Hoosier DR's. They are 48 offset (120-63 mm). Son gave wheels to me.... came off his Firebird T/A. He has 2 left. Of course I don't have Brembo Calipers.
