My 2015 GLA250 is coming with the 30mm raised suspension, but not until March-April (will post some pics for sure).
I did stick with the 18's and higher profile tyres for curb bashing (and less road noise), but this might upset the overall look making the wheels appear smaller (too small perhaps) with the higher stance. Edited by: Pip
The 18" five-spokes are a good compromise of looks vs practicalities, in my opinion, and definitely don't look too small - they're still big wheels! The slightly retro design of the five-spokes suits the urban-off-roader style of the car, and the Continental tyres have enough of a sidewall bulge to protect the rims, even when kerbing the car during parking. I've taken my car through all sorts of terain and situations, and there is not one bit of rim damage yet. The ride is very comfortable, yet the car corners like its on rails like no other vehicle I have ever driven (racing karts excepted), and I don't hang around. Conclusion: speaking from experience, the 18's are a wise choice.