Hi, here's my two cents, which may or may not help - I only have two Toyotas, a '98 Rev5 MR2 n/a running the 178bhp I think it is, and my '99 Altezza semi-auto which has 200bhp - I would say that if the BEAMS engine in the Altezza is a VVTI version of what I have in the MR2, well you couldhafooled me - see, the MR2 just GOES with a smooth surge of urgency, no matter where you are in the RPM range, but the Altezza (Oh, and I am SO not criticising it for this) is a Jekyll/Hyde device - below the 4000 RPM kick-in point, it is sm00th and torquey, but also relaxed. It feels quite like the Mercedes 2.6 straight six in the 190E - I know what they feel like, and with a blindfold on I couldn't tell them apart. Not sure why I'd be driving blindfolded, but there ya go. ABOVE 4 grand, it gets busy and hauls for the red-line - now to me, this suits the Altezza perfectly. I often have a few passengers who don't wish to go everywhere at Warp 7 - and if I'm in no particular hurry, I'll pootle along and amaze myself with the efficiency and MPG that this saloon can deliver. By contrast, the MR2 gets caned just about everywhere, save for obeying urban speed limits. I haven't driven an MR2 with the BEAMS engine, but I wouldn't want it to be docile, laid-back and relaxed at ANY point in the tacho dial. And then again, you are using a one-off turbo, which will change everything anyway. I don't know what you have done to lower static compression, how much boost you are using, how happy you are with it off-boost - I would just fear that IF it stays bogged-down till 4grand, that may be too much dead-space for you to feel happy with.
Perhaps merely going through a process of ultimate optimisation of what you have would help you gain a few more pound/feet on the way to a few more BHP? Thermostat, wrapping/zirconium-coating the exhaust manifold, fitting a few more heat shields, installing a Water/Meth-Injection kit if you don't already have one, then taking some mass out of the car and flywheel - again you may already have this covered.