Welcome to the addiction..... I can answer all your questions with one word, RESEARCH. Everything you asked is readily available without a lot of effort to find. I'm really not trying to be an ass about this either. When I did my build I gained a wealth of knowledge scouring every LS Z build log I could find. There are multiple builds on this site including info on your requested non-swap info. This in not going to be "cheap" by any stretch even with a total "budget" build, but I will throw you bone or two to get started on your info request...
-Kits: CX racing, Hoke, Dingo, JCI, Custom
-Suspesnion: AZC, T3, Silvermine, or just stock upgrades and add latter
Brakes: Willwoods for me (contact Silvermine or AZC)
Paint at 2k: Forget it
Dynomat: least of your worries right now
225 tires: not enough meat to hold the power
Driveline: Drive shaft shop or custom local shop
CAI: easy peasy at less than $200 with basic fab skills
Radiator: my 3 row champion works great in 110 heat on the track
20 gal cell: way too frickin big and no way that fits without fab.
Best of luck, Trackzpeed