I actually don't notice the engine noise anymore. If I do notice the sound, I enjoy it. Its like how people got used the the V8 grunt sound and say that sounds powerful.

As for the tires, I decided to stick with 18" mainly because all the concern regarding 20" ride vs. performance. I figure this decision can be changed anytime I want to. I can upgrade my tires and rim afterwards. I just don't like the idea of down grade. So 18" was a safe bet.

I don't regret it. I have not feel the need to change my tire. I am sure after a year I may change my mind and go all summer tire route.

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2012 BMW X5 Vermilion Red Xdrive35d with Premium Package, 3rd Row Seats, and Adaptive Drive