Took the MB out for a spin this morning & overall am satisfied driving it, with & without figure. Hadn't had a chance to run in dirt or gravel so expect it will be a bit more squirrelly with the figure. Its quite a peppy little bugger so with stiffer springs, it can only get better, especially since I always plan on having at least one, if not more, figures onboard. Shocks are standard 80mm so will be easy to change out with something better; am looking at adjustable shocks now on Taobao. Later I may switch over the rear shocks to leaf springs but that will be further down the road.
Since I was solo, I didn't get a chance to take any video but here are some shots alongside the Hummer for comparison. Again, with all the metal parts HG uses as standard, my Hummer weighs twice as much as the MB. In case anyone is wondering, I lifted up the driver's side of the body to straighten up for the shots due to the soft springs. The Hummer's suspension, on the other hand, is rock solid but a completely different design with shocks designed to carry the weight. HG certainly makes a very nice product!
Regarding upgrade parts, the manual does show some optional aluminum bumpers & windshield wipers (?) along with the canvas canopy & machine gun so who knows if anything else is forthcoming. Still am waiting to hear back from FMS on inquiries I sent regarding parts.