Seeing the wheelbot in action again really shows how much the combat bots have improved since the first generation.
The Scylla is an interesting design, and seems to be a good match for the mudslide, although the two bots seem to lose interest in each other after the first encounter. In my small arena, the better aim and higher rate of fire give the mudslide a bit of an advantage.
It'd be fun to add more cannons on each side to take it up to the parts limit.
Have you thought about putting the cannons inside the cylindrical armour section and letting them fire through it? That should keep the cannons fairly central and well protected.