Honestly, with a forced induction set up such as a turbo, header length isn't as important as when you have a naturally aspirated engine. However, with a turbo, you still need to avoid the turbulence. But most often, having something that is equal length will only take up room in the engine bay...
Does anyone know if the TRD supercharger for the smaller 3.4L 5VZFE would fit any easier than the 4.7L? I could probably ask around and find a place to mill adapter flanges for the 4.7, not sure. Sorry no good pictures of the 3.4L supercharger.