RE: Smartech Bigfoot
The nutech cars are based on a different chassis design.
What you have tere is also known as the Duratrax Firehammer, an FG clone manufactured by smartech and rebadged and further cloned by others including ShenQi. It's by and large a decent car, and you will find that a large range of spares designed for the FG Marder and FG Monster Beetle (as well as of course Duratrax Firehammer parts which are still around if you look for em) will fit. Most hopups for those cars should fit as well, it was a pretty faithful clone of the Marder based Monster Beetle.
If you don't already have them, you should immediately look into alloy engine mounts, the engine rocks back and forth and side to side on the stock plastic ones.