Got Maxis on my MTB too, really good tyre. Haven't used them on any cars or have experience of them but in all honesty I wouldn't fit them. Not because they are shit or anything simply that it still haunts me throwing out a pair of almost new Nankang NS2's that my missus put on my old A4 as the soppy bint decided to save a few quid. Tyres aren't cheap and getting it wrong can prove both expensive and dangerous.

Kumho is a tyre I wouldn't have touched, my brothers M3 came with the KU31 (iirc) on the back and I actually have to admit to being quite impressed with them, especially for the price