The main advantage of 2 into 1 exhaust is they scavenge the cylinder better allowing for a more complete charge when filling the cylinder. That is the simple explaination. Different brands have their proponents...I like my D&D Fatcat with the quiet baffle.....sounds good, not loud and the power increase is there....especially with the Thundermax/autotune running the other side(intake).
Hood, hopefully I will be building my HQ 103. I will let you along with everyone else how it works. I am not much on taking and posting pics, but I will keep ya'll informed.
Power is not cheap but if you want it there are good options out there, My best advice is do your home work and figure out what you want from a motor then research who is sucessful with that style of motor then see if it is in you budget. I was after tq. not concerned with hp and I wanted it there all the time. I found that in my H.Q. build. There are others who offer great builds as well and it will pay off reading as much as you can. Also dont get cought up in #'s only when and where the power is makes all diffrence in my opinion.