No need for 5 pages,
Reason I went with a rwd turbo setup when i first went turbo. I did work for my buddy and got a tubular rwd manifold, t25, and 3" greedy turbine outlet pipe for nothing. The setup cost me little to none. I was planning on running open downpipe anyways so the direction the turbo faced didnt matter to me. I could still fit my fans in place except one i had to put on the front of the radiator. Had to make a custom intake pipe, maf was running blow through so who cares. Other than that the turbo and everything fit just fine.
And you know what, It ran hard and nobody on there can say otherwise. On only 8psi the car went 13.0@110mph on street tires and 12.4@110 on slicks. So laugh all you want but i gurantee that tubular manifold outflows a BB or GTIR manifold by far. As far as the turbos go, there is no advantage one from the other. They are the same basicly.
As cheap as you can get a bb or avenir setup. I wouldnt bother going rwd setup. Again only reason i went that way was because i got the turbo stuff for nothing.