I run a 5.0 95 GT with close to 300HP to the wheels (EFI) and it hangs with stock Vettes.
I basically have heads (ported iron GT40 cobra), intake, roller rockers, TB , EEC Chip, CAI and MAF plus an offroad X pipe (no cats). Still with stock cam.
Also removed the smog pump but still run with the A/C.
For suspension almost every bushing is urethane, rear control arms, subframes, Tokico shocks and struts, linear rate springs, steeda balljoints and ccplates. It is streetable and does its work for ocassional road racing and autox.
It was a fairly inexpensive setup, and still have to improve it A LOT, will install a panhard bar next, and probably will go with a coilover setup at the front.
The first rule is modify your suspension, there are 100s of ways of doing so, some expensive some not so much.
Look at
www.MaximumMotorsports.com stuff, these guys know suspensions better than anyone. Another option is Steeda or Griggs but MM is my overall favorite.
The first suspension items to change are the stock rear control arms, the bushings (urethane), springs and shocks and some caster camber plates.
Tires is one of the first things you should look at, a good set of tires is worth seconds less from your lap times, and possibly this is the largest expense in the long run.
A good seat is a must, you dont want to be fighting G forces to stay in the seat. At least get a good harness.
Also..reinforce the chassis, get full length subframes and a rollbar, check requirements for your class.
The chassis suffers from twisting and the subs and rollbar will keep it straight.
Brakes..you dont want them to fade, this is not only a safety concern, but also a speed problem, you want to be able to go as deep as possible into the curves. Cobra brakes are nice, but for true race performace go bigger if you can: Baer , Brembos.
The class you run will dictate which parts you can modify, so check at your local track.
Some tracks will have open doors for newbies and practice a few days a week, the best way to know is to ask.
You dont have to be hardcore to have fun, you dont even have to race against others, just going around the track alone makes you smile for several days
My advice is to learn as much as possible by reading and asking, when you hit the track you will know at least some basic rules.
We have a few suspension tech articles that can help you with mods and how the mustang suspension works and its limitations.
Newb with a few questions about road racing a 5.0.... 
