Welcome Dan,
I was faced with the same question about a year ago when I bought a 98 SVT. Its a fun car stock, but as you will, or have seen, there are many mods available. I bought three items right off the bat: 1) Intake, Y-Pipe and Underdrive pully set. Due to purchasing a set of MSDS headers, I ditched the Y-pipe and am using the MSDS supplied one. I have also replaced the underdrive pulley set in favor of a DMD pulley. I think it is important to do two things before buying anything: 1) make a plan; decide how far do you want to go, what areas are important to you (i.e. engine, brakes, handling) and how soon do you want to implement the changes, and 2) how much do you want to spend. Post again with some more info, and I will give you me 2 cents.
