BMW ideas would be the way to go, start with the E46 M3.
the main hurdle isn't the components required, it's the tuning and like you said the runner lengths.
ideally you would initially get adjustable runners and spend hours on end on the dyno to get it right. then you would get the CF ones fabricated at the set length. however the minute you change timing, fuel mixture, tune, etc. the lengths may need to be changed again. each variable affects one another differently and each time you modify the 'optimal setting' shifts.
that said, you would only do that if you were chasing the last poof-teenth of a kilowatt. most people don't care.