Make some upgrades to the engine (i.e. headers, performance intake, heads, cam, adjustable fuel pressure regulator, injector spacer, etc) and then have a custom chip burned to your specs. With a tbi motor, you have a small cam selection that will work with the stock chip and heads will require a new chip. You can get away with headers and an intake with the stock chip but its a good idea to buy an adjustable fuel pressure regulator and guage to get maximum gains.
Once you have all the hardware goodies, call up tbichips or similar company and they will ask you your year, motor size, all your performance upgrades, tranny, and rearend ratio and burn a much better chip. And if you have a laptop you can always buy or make a connector and download winaldl (a diagnostics program) and do some data logging. Then you can give those figures to a good chip burner and you will have a perfect chip. That...or you can buy the stuff and burn your own.
Hope this helps.
-Harrison