I am currently running a similar setup in my 02 RS. I'm running an STI shortblock with forged internals and RS heads with a borla NA manifold and stock exhaust. it is currently running off the stock ECU without reflash, but will be using a Hydra for EM in the near future.
Currently, the car drives like a stock RS. (handling is different because of suspension mods) not sure of the HP, but rev limiter is still set at 6500.
I plan on adding a turbo to the car in the near future. All I will need is turbo, intercooler, turbo exhaust manifold, up-pipe, Turbo-back exhaust, larger fuel pump, larger injectors, and a re-tune of the Hydra. I would also suggest larger brakes
hope this info helps