does anyone know what the differences between the 65mm high flowed throttle body from RPW, to the stock throttle body on the TH magnas

Yep. Inside the stock throttle body, just before the butterfly, there's a 3mm lip. RPW (and others) grind that lip into a gentle slope.

Result - less turbulence at small openings and better throttle response

There is also some metal can be removed from behind the butterfly. Leave some of that front lip though so that the butterfly can close and seal properly or your idle will become hard to control.

The line of flow at the top of the tb sux ar5e too. This needs to be attacked. Basically need the flattest line past the butterfly possible without affecting idle rpm. I.e. DON'T TOUCH THE BUTTERFLY SEAT!