Some here have been here long enough to remember the ATP debacle with "Wunderwagen" and his great variant. Dave's machine was "sponsored" by ATP and what a cluster-f!ck that was. In effect, his car was the test mule for the T03/T04E programming and installation.
The day he showed up at an ND Show at Moffett, they (George at ATP) didn't tighten down the exhaust manifold; according to Dave it almost fell off on the way to the show. Then he pointed out the nice anodized BOV just ahead of the TB. Very nice looking and custom but when you looked at the tubing, it was rubbing against the bulkhead - again, Rev A. of their installation. HE also indicated they STILL had not gotten the programming correct and this was 6 months after getting the turbo.
He has since abandoned ATP. ATP in turn has realized they don't do good installations ( YOU THINK???) ; from my last conversation with Dave about a year ago, I "believe" they recommendTomas Motorsports up in San Pablo (30 minutes north of where ATP is) to handle installations so they could concnetrate on building these GT series turbo's.
But you're all correct about a couple of BIG issues: exhaust manifold and programming; add injectors, MAF, etc. I'm sorry but there's no "magic pill". If you're going to do this right, do it from head to toe: from programming to MAF to turbo to IC to TB to injectors to FPR, to exhaust manifold, to cat, to exhaust. And remember the DV upgrade.
I've given up on the chase for now. Rusty holds some promise for the AEB/K04 crowd with his continued testing in uncharted waters. I'll just be happy if someday I can just reach 240hp and/or 220ft-lbs. torque.