I'm going to assume that your Sportivo is running 14's or so (edit: hot car by the way, but in your garage it says you hope to run 14's? For my curiosity has it been on a strip yet?). Spend the money you've spent on it (about $1500 going from your garage, plus $350 for the uprated rubber) on an S15 (or an XR6T) and I'll be dumbfounded if they're slower. Another few grand on either should see you running flat 13's if they aren't already, possibly 12's. Sure it's not a granny hatch, but it's ultimately faster, and what KaZe-StiVo is after.
A piggy back computer is a waste of money; $500+ for a paltry 10kw gain? And I'm not surprised Powerchip haven't considered the 2ZZ; it's already a massively high-strung motor. I know it's a Toyota donk, but how much further can you take it beyond economical sense? (I realise a lot here have, but it's not without risk). You might as well get a Microtec or something and have the ability to tune everything with regard to the fuel you're using, how you're driving it, etc etc.
I have to agree there man. Pour $5000 into the engine bay of an S15 and you'll get 12/11 sec quarters. That's only one car as an example as well.