The spool is close but the midrange is better on the GT3255E. Top end on both is awesome.
If you are going to do mostly street driving the Gt all day. Put it this way Mike @ full throttle says that the GT is 40 ft lbs more on the dyno than the TA-49.
Heck, he was so pleased with the Gt series turbos that is all he carries now and that says alot coming from someone that is been in the business as long as he has.