The Mini-Z stock motor is roughly 70 turns and somewhere around 27-28k rpm unloaded. It's actually surprisingly fast, I would put it in the Xmod Stage 2 range for power even though it has 70 turns vs. 49.
MR01 is around 180g (with batteries and body), and Xmods are 210-220g IIRC. The weight difference is quite large.
The MR01 has no servo saver so if you smack the front wheels into a wall, the servo gears inside the white servo casing (or black, if you have a very early MR01) can break.
You can soften your rear tires by rubbing WD40 or simple green into them. Or you could buy new tires for $4.