215 tire is more realistic. And *I think* performance may be subjective. 15 and 16 inch wheels weigh less than the 17's, however, 17's have somewhat sharper turn-in response.
16's are a good compromise between decreased weight, still keeping similar turn-in response, and helping to improve grip with a wider tire.
I prefer 17's just to keep the sharp turn-in performance, and I run Konig Hypergrams with 215's. I have never run 16's, but plenty of people on the forum prefer them. Might be something to look into for decreasing unsprung weight, and increasing contact patch with a wider tire. Both of those will increase performance/handling.
Edit: Also, welcome to the forum fellow NC native!