ive owned 3 over the past few years
drop in some $15 exi or mg servos,
pop on some proline or similar aftermarket tires
cut the stock foams
add some lead weights
And done, it will crawl very well like that. Even with just better servos and cutting the stock foams it will be good.
I did limit the suspension a little with some shock adjustments.
The rc4wd outcry duel motor esc is also a nice upgrade. It has turbo bec, and can handle 3s...which gives the rig more wheel speed for slick rocks.
I never had any issue with the stock ESC myself. I only went to the outcry for more wheel speed and the turbo bec.
I broke a suspension link end once or twice. a shock end one time.
I never had to replace trans gears. And you shouldn't unless you do the 540 motor mod or upgrade to 380 brushless motors. IMO, there is no need to go that far.

If you want a sub $300 rig that will out-crawl a axial scx10 (even modded) then the rs10 will do that. even out of the box the 4 wheel steering (expecially with 4 modes) gives it a huge edge over other budget minded crawlers as well as even the losi NC or AX10.

How did you spend 1k on the 8e? The servo sucks, the steering bell crank needs upgrading and the diff upgrades are needed. Other than those things I was happy with my 8e, which I did bash. It is no HPI savage, but it can go pretty hard and pretty fast for its cost.
They have a new 1/8 brushless monster coming out soon.