New E-Maxx 3905-=reliability=-???

I've a great deal on a use (2 packs trought it) 3905 e-maxx and i'am plan to run it with a Neu 1515 2y and 6s lipo.
How is the durability of this truck, what's the most fragile part on it?

What about tranny and diff??

Do i'll have to upgrade drivetrain??

And for the pitch gear, this is 32 or MOD1

If it's 32, can i use revo spur without any modification??

Thank you!