Square Taper or Octalink ?

Q factor's only an issue for the pigeon toed.

You can stiffen up every interface between bike and rider, but any improvement in output is miniscule compared to the gains made by training the 'engine'. It's a money pit. Just look at the results in the recent Planet-X Old Skool series. Even with the technological advances that can surreptitiously be added to bicycles fit for the Merckx hour or whatfuckingever, no-one's coming close to the records set by athletes who worked a whole lot harder, back in the days of 3-day weeks, square tapers, box rims, and shit.

(I meant the issue of q-factor as in compatibility for manufacturers, with the 42mm chainline and narrow q-factor required for aerodynamics, and to a certain degree, track clearance)

the old people only went fast because old stopwatches weren't as accurate as modern ones