Ringa,
after a lifetime spent modifying bikes I learnt long ago that exhaust design is a mix of art and science. The science is all to do with pressure waves, back pressure and flow rate. The art is getting it to look right and to sound right... It is possible to have an exhaust that sounds wonderful but is quieter, on a db meter, than one that sounds harsh and aggressive.... It is also possible to make an exhaust that sounds fantastic but makes the engine run badly and develop less power than the stock exhaust.
At least the S&S twin functions, from an exhaust perspective, as two singles, no crossover or balance pipe. But I hope MMC spent more time designing and testing the exhausts than they did the transmission... Has anyone taken a M3W to a bike exhaust specialist like Zortstec or Armour?
