Use 03 cobra pumps and tank, period. If you want to make more power then use a cobra tank with focus pumps and a BAP wired correctly. The walbro returnless pumps are a gyrator pump (like a lobe pump) and cannot control pressure very precisely, they also WILL fail in short order. The 03 cobras use a turbine (centrifugal) pump which is meant to control pressure in small intervals.
The aviator pumps are NOT a viable solution, IMHO, you have to use a aviator FPDM and then attempt to program the PID controller correctly, very few people have luck doing this, and those that do spend a LOT of time getting it to work correctly.