QUOTE(horizontally-opposed @ Jun 3 2018, 07:52 AM)
Ideal sizing discussions are meaningless for 15s (or any wheel size) without looking at what's available. The only 205/60 & 215/60 combo—which I agree would be fairly nice on some cars, though maybe not as nice as 195/65 & 215/60—out there that I can think of is BFG Radial T/A if those are still available in 205/60 & 215/60. But then the discussion is focused on how good the BFGs are as a tire for a sports car, and all signs point to not great. There may be some other tires available in 205/60 & 215/60, but I am betting they will be all seasons or Camry tires.
The good news is 195/65 & 215/60 are available in some very good tires, from P6000 N-spec to CR6ZZ, CN36, and maybe 1-2 I am forgetting. None are cheap, but they are a nice setup for a 914 on 15s with flares to cover the rears.
205/50R15 + 225/50R15 sets are out there with 2-3+ choices between Pirelli and Toyo, but they are aggressive.
Oddly enough, 16s may now present fewer options than 15s...
agree 100% - b