Hmm, sounds like something is missing or the power limiter is on slightly, but I'm sure you would have checked that and that all parts are fitted. The car isn't high mileage enough to lose that much power.
Which turbo are you using? The stage 2 gives slightly more HP and a lot more torque than the stage 3 turbo.
The most I have EVER gotten was 726 out of a broken-in and overhauled ticket prize. 740 is impossible without illicit modification. Mileage is the biggest factor in the maximum potential of a car, and permanent wear (which can't be reverted without a car restoration ticket) begins around 5,000 miles.
The restore ticket he is referring to isn't a free rebuild, It's a ticket that takes your car and returns it to 0 miles(unbroken in meaning No power loss.) that's where your power went. I have a RZ with about as much power as your's. besides you really thing a hybrider is gonna waste 30-45 mins of hexing to gain a mere 14-5hp? The engine overhaul only restores so much of the original power. best bet is to ask around the Market place for a lower mileage Supra RZ and see for yourself.
I don't understand "hybriding" on any level, I mean I get why people do it but that isn't enough of a motivator for me. Then again, I don't even cut chicanes.