a pipe doesnt care how tight a bend you have. the pressure waves take no notice of how sharp the turns are (my first pipe had 1 bend, almost a right angle, that was just a plain mitre, not a smooth curve).
the exhaust gas does like some "aerodynamics" though. just so it can flow without turbulence.
think of plumbing. smack the end of a pipe with your hand, and the pulse is felt at the other end, regardless of the number of bends and twists.
whereas water (a fluid) wants the straightest run possible to flow as fast as possible with minimal turbulence.
what does affect a pipe is changes of section. if you flatten it at all, you need to recalculate length and angle of taper... the reason why i went up and over instead of down and between the cranks. theres only 30mm clearance down below when i needed 70mm at least...
just made it easier.
as it is though, i can make exactly the same pipe as a straight one, or (if i tried) all curled up like a tuba... the basic dimensions stay the same.
low end? huh? never use it. but yes, it will putt along without needing to be pedalled, with almost no throttle. like when passing policeymens...
its the long 4km uphills that wear it down...
little ones, no problem, it has a run up, but id go lower gearing if i had to deal with more hills
when i get the license back and these can become nothing but a hobby ill do a monster pipe for the stingray... about 6ft long. wont rev but should make some low down grunt