i suggest u know ur priorities first... if you have a HP and/or 1/4 time in mind then ur on the right track. now would the basic I/H/E be enough to reach that goal? If so you then go right ahead, if not i'd think about goin' either NA + N20 or TURBO.. but before you go either route i'd suggest taking blind34_1's advice on replace and/or upgrade what you got right now (if its mileage is up there)
As you can see, setting up your priorities will save you money, time and effort, best of luck to your project...
oh, btw.. Welcome to HST