I feel qualified to chime in on this one. Prior to buying my Stingray last month, my only car was a BMW 528i that I bought new in 1999 - still have it. Do you know, even to this day, that car has not had even one rattle - not one. I have 176k miles on it. No doubt it is the best car I've ever owned. Has it had other problems? Of course it has but those problems have been few and far between. As much as I like my Vette, if I could have only one of those two cars, I'd still keep my current BMW. Certainly not b/c it's faster but because it has been utterly reliable - still has the original engine, tranny and paint job with no major work on any of them. Back to the M4 - I really can't say that the M4 is of higher quality than a C7 b/c I've never owned an M4. I did test drive the M4 before I chose the Vette though. I probably would have purchased the M4 had the exhaust not sounded like two kids shaking marbles around in a tin can. I can say for sure that the M4 auto tranny felt better than my Vette's. My Vette's A8 searches for gears a lot - too much really. The M4 tranny was more decisive. I hear a faint "ticking" and a very mild "puffing" from my Vette engine that probably isn't a real problem but it shouldn't be there. I didn't hear any funny sounds from the M4's engine. The interior of the M4 seemed a bit more refined but only slightly quieter than my Vette's. I'm hearing a slight buzzing noise in the interior of my Vette near the passenger side door that I haven't figured out yet. It's a little annoying but I'll find it and fix it eventually. I get hot air at my feet in the Vette while getting cold air up top - don't like that. If I drive for more than a hour, the A/C in the Vette can't seem to overcome the heat coming from the tranny unless I turn the temp way down and the fan wide open (but I still get warm air at my feet). The Vette has some programming issues related to its infotainment system that could and should be remedied by GM right away. But, the Vette sounds meaner and looks sexier and it really is a lot of fun to drive. I'm sure the M4 is fun to drive also. It was a tough choice for me given my experience with BMW. I knew there would be some issues with the Vette and I plan to do what I can to tweak the car until it is perfect - to the degree that I can. Should I need to tweak a $70k+ car? No, not really but like a previous poster stated, BMW is not as good as it once was and it'll have issues too - different ones likely, but issues nonetheless. BMW have cut some corners over the years and lost some of their good reputation because of it. No, I wanted to reward GM for their serious effort to bring the Corvette up to modern standards. Even though I feel that they have fallen a little short of my expectations (just my personal opinion), I don't plan to give up on them. Not yet anyway. GM does need to address (i.e. FIX) known issues though - like yesterday. I plan to keep the Vette and give it a fair shake. I'll be fair about it but GM, I hope you're listening to our complaints and that you plan to fix them FAST. I don't mean on the 2016 model. I mean for those of us who have already invested our hard-earned money in your product. Don't let us down.