I saw a crf450r w/ twin pipes in DB magazene. fmf already has a dual ex full race ti. system out for it that is quieter than the stock system. Fmf has already tested the same system on the rmz 450. I don't think it would be a giant leap for fmf to make the same system for yam. They could posibly get nois down to around 85 dba w/ all that chamber space. The main reasons honda claims they came up w/ twin ex. was to centralize weight. The question is would you pay $1000+ for a dual ti system that is as light or lighter that stock. gives you better handeling and less nois than a stock 4 st mx bike. I mite if I had a brand new bike. Oh yay did I mention a gain of 2 hp at 3000- 5000 rpm and a 4.5 peak hp gain.