The reason I said there's something wrong is/was because 536 RWHP (so around 600hp at the flywheel) at such low revs is almost unheard of. Then you said it has 272 cams too, which don't exactly promote early spooling either. Just doesn't make sense to me
Also I was asking what you meant by 2.5JZ thinking that maybe you meant you had one of those 2500cc affairs, which would have made it even more unlikely. Any road, you've corrected some of those things now, so it's bit a more credible.
TBH mate, I don't think you're going to do any better than you already have. If what you're saying is correct, you already have any amazing setup which would be very difficult to improve upon.