Karzza made an interesting post which I'd like to follow up here in a separate thread.
Audi/VW 1.8 turbo is using a similar type (Weber) fuel regulator than V-Rod. An inside diameter of a fuel return drilling is smaller than V-Rod's, so it would be risky to use Audi's regulator, especally with an hi-pressure (gear type) pump in V-Rod.
You can use billet cover made for Audi with V-Rods original regulator, to get a possibility to adjust the pressure and to follow intake manifold pressure. Cover needs some modifications to get more space for the throttle linkages.
Vacuum/boost control hose have to be connect to intake manifold, not to plenum. (some turbo-kit supplier are connecting this control incorrectry, like IAT, MAP as well)