This is my situation as well. Lots of life left in my OEM tires, so I'm using them.I put my stock Potenza's on a 8'' wide wheel..the tire doesn't look bad, mine looks pretty much the same as Wastegates..handling is not quite as good with the slightly stretched tire if that is one thing your looking for. Most of us aren't being cheap, we just see the need to use up a set of tires before replacing them.
Next set will be 225/40 or 235/40.