I put 195/70 - 14's on my 85 2M4 instead of the 60 series and I really like them They not as wide so the steering even at low speeds is fairly easy and the car handles lighter too which makes it more fun. The 60 series tires on the 4 cylinder were not necessary and were put on for "appearance performance"
You can go to a 225 without issues. There were also some of the coupes that came with 75 series tires, so that may be an option. Check with Tirerack.com They have BFGoodrich in a 225-60R 14 at $109 each or if you want to stay with the 215, they're $123 each. They would probably be shipped to you out of Midway, Ga. (Savannah). NTB is an authorized installer so you might check with them to see how their direct sale price compares.
The '84 brochure shows 195/70 R14 & 215/60 R14. On my '84 SE with the GM Hi Tech aluminum wheels I've run 235/60 R14 without any fitment issues but they looked a little plump so the last few sets I've had were BF Goodrich Radial T/A 225/60 R14.