We went from avgas to mogas in our 160. We were getting lots of rubbish buildup on our pistons after only a few hours from new and we were often getting crap under the exhaust valve meaning bad leak down figures.
After going to mogas no more problems, good leakdowns and no more issues though it is harder to start and the cabin now smells of fuel!
We run our engine at 2900 most ofthe time and have since new so we don't baby it. I won't be going back to avgas.
Also on wing loading, the wing loading depends on the weight of the aircraft vs the wing area. With the 170's higher mtow the wing loading between the 160 and 170 probably isn't that different at mtow.