[JAM1775]

If your primary header pipes merge into one large pipe with a flange on the end then bolt to a curved singular pipe to exit the body and flow to a muffler I see no negative consequence. If you use a good merge collector you might even make more power . As far as appearance a nice 3.5-4" pipe turning out at the body maintaing a smooth flow stright thru the balony tip looks pretty nice ! On the FFR forum they did muffler dyno/DB tests. We have an option of 4x4 or a singular "J-Pipe" at the end of the header. If I recall the J-Pipe when fully ported made a bit more power than the 4x4 's. Then again the stock FFR 4x4's collectors have a horrible gap inside where all 4 ports can actually mix / collide. I had mine filled . milled then installed merge collectors with the spike inside to ease the transition from 4x4 to the muffler. For power and better sound I think it is more about velocity and smooth flow control design than the difference between 4x4's and a 4" tube coming right off the header.