Nice build you got going here. I like the design a lot but I'd have to aggree with Mach Crit, the guns are looking good and I like the realistic proportions but it does seem a bit of a puny weapon setup for such a relatively large body.
An alternative might be to incoprorate the two guns in one dual mount, that will immediately give some more volume and balance to the look of it all. On the other arm you could put a missile launcher for anti-tank/aircraft/structure engagements.
Something like this springs to mind
http://www.armyrecognition.com/Ameri...Us_Army_05.jpg http://www.aaamodels.co.uk/List_Pics...405_LAV-AT.JPG http://www.ipmsstockholm.org/magazin..._lav-at_36.jpg http://www.armyrecognition.com/Ameri...Us_Army_06.jpg http://www.armyrecognition.com/Ameri...Us_Army_03.jpg