I don't have one to hand, but I have seen a T04Z overlaid on my graph of GT-RS terbs and the response is basically identical when running standard RB26 cranks. The T04Z runs away at the top end providing an additional 50 rwhp or so. I can't comment on how they both would compare on a stroker crank, but I imagine the response on the T04Z would improve as it does with the GT-RS.
In hindsight (what a wonderful thing eh?) I believe that there are 3 choices for the HKS junkie when upgrading an RB26:
GT-SS for a fast streeter
25/30s for a good track car
T04Z for track/drag (or streeter with a stroker crank or RB30)
Still, it's kinda nice to be different and make decent hp with low mounts