ejbta2

check my sig for mods, my heads flow 200 cfm on exaust and i am running mac mid length headers with 2 1/2 collectors (keeping the headers) and stock size pipes with a flowmaster. i think its killing my top end i should have about 400 at the wheels but not with this exaust. i am debating between duals and single(because of tailpipe cut outs in the rear) can anyone help me with suggestions and maybe some pics they would be appreciated.