[NOT A TA]

I think it will come down to tire availability. There's currently not enough options in the 14-15" high performance tire market to please everyone AND I don't know if tire manufacturers could, or are willing to try to design, 14-15" tires that could match the performance of the shorter sidewall 18" performance tires. Sales of high performance 14-15" tires would be a very limited market at this point.

I've moved up to 18's on my 2nd gen Firebird which is more of a road track car, not only because of the brake clearance, but also because the options in DOT R 17" sizes has started to dwindle.

I've got an 81 Malibu street car I'm building with a sort of backdated look. 14" wheels with radial TA's, not much out there for performance 14" tires.