Its funny i was just reading on another forum of a guy with a Supra saying the Nissan GTRs bog down on the line and his Supra does not,

A different boost controller cam make quite a difference, some of the best ones have anti- lag programs built in, and are fast with a quick response (run at a high frequency) the Profec is an old design

Even the pick-up ponts for the controller sensor can make a difference

Im just thinking out loud but a shorter, fatter single pipe exhaust - perhaps a side exit, and a heat-wrapped exhaust manifold may help (if its not already)

I run an anti lag system that shuts the wastegate virtually the moment i lift off so the wastegate is (always) shut automatically when i go back on the throttle, it only makes a slight difference but it all adds up- and if you are drag racing even a tiny advantage may mean the difference of winning

A smaller (internal volume) intercooler (with waterspray to compensate), shorter boost hoses or an water/ air chargecooler (with ice tank for your races) - im sure you have though of these already!

Ithinkthere are a lot of people that wish they had your problems!