think best recorded road car for vtr (black top) that im aware of had 123 at the wheels and bags of torque with bodies and cam, although that didnt have an airbox as such.
im not an expert (at anything) on bodies, but basically you need to decide how you want the car to drive, short trumpets=high end power, long=bottom end etc, so you tend to compromise, the GMC curved trumpets for vts are supposed to give the best length and also give great torque through the range.
If you want to keep your vtr then think you can get enclosed airbox for vtr with cold air feed that shows good gains, although i think it will muffle the sound a bit (the good part

)
Also no point in getting TB;s unless your getting some cams to match in my opinion else might as well stick with single tb.
Thats the whole point of TBS to give the cam better breathing per pot, so you can get the most out of it. Not the other way around