what year CSVT?? then we can really help
oh yeah and gut the pre-cats, its a good mod, also the y-pipe optimization is really good
people have problems with the MAF's because they kinda bypass the PCM they tell it more air is coming in then there actually is and so it can cause your engine to run rich, its not a good thing to start with(i think that is how it works)
best first mods would be
mod 1
THIS HELPS OUT A LOT, TRUST ME
mod 2
this helps a lot too, but not as much as the first
this next one is a must even if you have exhaust you need to do this
mod 3
you will also need some mil's when you do this so here is a link to make those
MIL's
next comes the really easy stuff
get a MAF adapter and a k&n ru-3530 cone filter, next get/make some sort of heatshield
after that comes some more expensive stuff like a LSD, flywheel, clutch, Returnless LIM, Port matching Manifolds, MSDS headers
only cause im feeling nice today, next time like the others said search