NCT5s are ok... but not a patch on the F1s - they are aimed at a different sort of driver
I bought mine thinking the same as you (good company credentials) - and my NCT5s have lasted a long time, and to be fair I haven't had F1's on the BMW so it isn't a true comparison, but they seem harder - higher silicon(?) content I believe for increased MPG etc etc - and therefore less grippy
I had F1s on a more powerful/unforgiving car - they lasted for nearly 20k miles and gripped unbelievably well even when down to the wear-bars - I only changed them as the MOT garage insisted!
I think the F1s are in another level - I have P-zeros on the other car at the moment (a pal kept on recommending them) and they are good... but not as good as F1s. I can't wait to get some more F1s when the P-zeros wear out!
But this is in 205/50/16 size, so the answer to all your questions is to buy some 16" Hartge wheels
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