Where do l get a hifow throttle body four tj magna vrx do l by one from rpw

From what I have read on this forum your money is really better spent elsewhere.
All one does is means you don't need to press the accelerator as much initially, but doesn't give any extra power.

Can make the car a little jerky on initial throttle application too.

I've got a spare half flowed, that is one side has been smoothed out, Non TCL, with cruise TB if your interested. It's off a TL/TW Manual car. PM me if interested.

Name "high flow" is actually misleading. It doesn't flow more air, you dont change the diameter as such, all it does is creates illusion of better response under light throttle, which is accomplished by grinding down the step before the butterfly. So its essentially the same as pushing your accelerator bit harder.