Looks like there'd be clipping if the side guns were firing forward and the top gun was firing left or right?
I think you need some sort of gear mechanism where the legs join the chassis, and perhaps some feet.
I'm unsure how you managed to get that over 1000 polies though. You need to evaluate the efficiency of your modelling, as that could definitely be done with under 500 polies with little to no detail loss. The cylinder the main gun sits on, for example, could be eight sided and Spring's smoothing would ensure it would be as round as it is now, with half the polygons. Same goes for a number of other areas. Front panel could be textured on rather then bevelled, etc, etc.
The chassis could do with a little bit more imagination, I think. It looks too much like a cross between a family sedan and a set of drawers.
Spring will only smooth items designated in a smoothing group. For example, you would designate the edges of a cylinder as a smoothing group, and that would appear round rather then faceted. Otherwise, the edge appears hard. You should be able to do this in whatever modelling program you are using. Unless it's rhino, which makes it somewhat of a nightmare (my modelling program *Facepalm*)
Try to look at the model from TA cam distance, then you'll see that you can't tell the difference between a couple of deformed cuboids and yours with all those extrusions, ergo remove them, paint it on the texture. Or do both and see for yourself.
