Bad ass bro, i built a 13B street port 6 port for my old Notchback VW i was doing many moons ago same set up as you down draft mani with a 48 IDA bored out to a 51.5. I ran a set of MSD 6AL and coils and all racing beat shit. Damm good motors, Also there is a place in Signal Hill,Ca called Mazda Trix if you need any help with parts or what ever. Cant wait and dont forget not 1 but 2 mufflers.lol