@TonyM995 , I'm not saying the big single TB wont have any response at all, I'm saying I don't see any reason to replace the stock TB's as they are already DBW / E-Throttle and ITB's work very well for a high revving 4 cyl (which is shy the oem's use them).
Also, if your goal is really over 500HP, I would 100% recommend using larger head studs in the engine. 500HP can be made with the 10mm, but it is a worthwhile additional cost to use 1/2" studs.
As for cost difference in making a "Race gas" system verses Methanol. the main difference is the cost of the pump. Methanol automatically removes the streetbike part, other than the ability to brag that you could ride it on the street. Pump options are basically a Protec pump or a mechanical pump. There are some other mechanical pumps, but they really aren't rated for high pressure and draw alot of current. Even the protec pump is borderline if only using 4 injectors and a higher base pressure is needed.
700HP+ on methanol can be made with 2200CC injectors, although they are at their limit. 2600CC are more suited with using only 4 injectors. More than 4 injectors are a better option if you were to make a multi-fuel setup or want any real drivability when trying to make huge hp.
Making outlandish HP on a bike is really just for bragging rights and unless the bike is raced, really has no place. You will very likely be completely happy with a 350HP bike, especially if you dont have prior extreme power turbocharged bike experience.
John