I thought a RAC2 should go on this when it was first announced and the official name was Street Sweeper. It's tanky as hell, runs faster than other Urbies, and totes a (relatively) big machine gun. With the removal of the 4th laser and the recent RAC2 buff, this fits well. Hilarity is sure to ensue:
I'd probably try to work towards a RAC5 and 3ERSL instead. ERSL have a more lenient range and RAC5 still deals significantly more damage. Ammo may be an issue though, so if I'm unsuccessful, I'll switch to this
I enjoy using a build similar to this. Mine mounts 1xRAC2 w/3 tons of ammo and 3xERML's for a little extra range and if I remember properly an XL 190. I've experimented with the RAC5 build and it can only carry 2 tons of ammo without sacrificing too much speed for my tastes. Also the extra range on the RAC2 makes it super annoying at greater distances. RAC2's don't do a huge amount of damage all at once but they are great for keeping your opponent's heads down.