I've raced the Matrix for the past year for the factory. Now I race for Mugen Seiki. The MBX-5R is a better car out of the box than the Matrix Pro. I had to make parts for my matrix and run other manufactures parts on my Matrix Pro to make it go around the track fast.
PM me and I will explain in more detail.
ALSO, so you know, Notch and RC10GTR <--- (Ken Wu the owner) both work at CEN Racing