'
whats your wheel spec plz?
It really depends on the quality of the wheels and tires.
It took me over a month of deliberation and research before I bit the bullet and went with 22" wheels. I was also worried about MPG and ride decrease on the CX-5, in fact CX-SV answered some questions for me as well! What pushed me to my final decision was that if I was going to spend over 2k on wheels for looks, then compromising to save $$ on gas was silly. Might as well spend the money on something else.
After driving around, here is what I found. Yes, there is no way getting around that MPG and ride quality will decrease, but my 2 door coupe had a rougher ride. As for MPG, I decided I could compensate for the weight by accelerating slower and driving with hypermiling concept in mind. Just by driving a little slower, I am happy to report that I've only lost ~.5 mpg off of my avg mpg.
And for that, here is what I gained.