I was wondering what your main intent was with the tank, such as build for display, back yard running, club IR battles, etc.
You will get many opinions on this, none really right or wrong, it comes down to personal choice.
Most of mine are intended for use at club meets. My philosophy is to avoid too much weight (metal parts and tracks) and run upgraded gearboxes in order to give a longer life out of a battery charge and have the tank able to move over longer grass (rather than sink in) in the times of year when we can't cut the grass as short as we would like. Unless all of your suspension is upgraded, metal tracks sometime result in more breakage, at least in my observation.
You will likely get some opposite views and ultimately, it is the individual's choice on what they run.
If you are buying from Immortal Hobbies, the owner, Curtis, tries to make sure the customer is taken care of.
"Luck favours the prepared!."