There is a bit of room for Light Ferro. Only gets you a half ton-ish. I would consider dropping down to a MRM30 to get a light engine to fit.
5/5, Absolutely wonderful, but there is no early game engagement. Mid and late game, this is a good brawling build. I did go with LFF armor, and picked up extra ammo. Runs well, even in on hot maps.
I like the idea of putting a light engine in there, but what if you downsized the SRM instead of the MRM? Also lets you alpha strike with both MRM and SRM without getting ghost heat.