Dual POP, Dual MAS, added the S-AFC and swapped the 2 1/4" crush-bend Borla for the 3" B & B on my car with stock heads/bottom end and the TD05s years ago, and I dyno'd 426 with the single POP and low-mid 430's untuned, 441 tuned with the dual POP. So, ~15 HP difference which was IMHO attributable to the exhaust and tuning.