Theres a world of between 8000 and 10000. I'm not trying to crap on your build, and really the ability to change gears wont affect absolute power which is what we are all really concerned about - all i'm saying is that the nature of synchro gearboxes is that the more you rev it, the more effort is required to shift as the syncho cones struggle to slow the shaft down to engage the gear - right up to the point where the gear will not select. That's why gears shift like butter under low load/low RPM conditions, but require monumental effort when you are out on the ragged edge at the drag strip.
ITBs are cool, but have you considered a long runner single throttle tunnel ram design? Tunnel rams (if made correctly and tuned correctly) will utilize resonance to actually boost air pressure (to the tune of 7psi at the valve in some extreme designs - but 4psi is quite easy) and push VE through the roof. This is the design of choice for Pro-stock motors and the effect can be amplified by pointing the air-inlet forward and outside the body of the car, creating ram-air effect as well.
Cost wise, the fabrication would be more, but materials would be less (1 throttle as opposed to 6), and tuning would be far easier - it just wont look (or sound) quite as sexy as ITBs. Thats not to say ITBs don't have their advantage. Brilliant throttle response and passive cylinder filling that no other intake method can match - but they wont focus the power quite as well as a tunnel ram.
Again, i have the maths for all this if you're interested.
