Your stock set up reduces boost at upper RPM's, it's merely reduced in the UTEC set up as to how much it cuts back.
Like mentioned before, the stock turbo is very small, very efficient and isn't made to produce major horsepower, but better drivability.
With and upgraded turbo, VF22, VF29, VF34, and a tuned by a TXS certified vendor on a dyno, you will be glad you stuck it out with UTEC. There is a MY02 with Pinks, and VF24, only things I don't have, tuned, putting 350 to the wheels on race gas... he has the dyno chart to prove it. Typically this set up is good for 300-320 at the wheel on 93 I think. I can't wait to get mine tuned.