dude. please pick a point and stick with it.
so far you have said that each independant chassis is the best.

mike kojima is probably running a b14 because he had an extra one laying around.
and has already had 234234231 b13's.
and who cares anyway.

simply put. b13 with coilovers will be better than a b14/15 with the same coilovers. due to the crappy solid rear axle.
and just a hunch, im sure kojima has put just a little more engineering and knowledge into his car than most.