I beleave that the 60T spur gear is stock for the 18MT, because of the larger tires. 55T for the 18T and 18B. But I could be wrong. There are also 2 spur gear covers for under the chassis, one is labeled T for the 55T spur and MT for the 60T spur.
3s with the 8k motor should be fine especially if you will only be running on pavement.
I have mine setup with the rx in fron in the motor and the esc on top of the chassis brace.

That is how I have mine set up too. Works great! Just need a Lipo now and I'm set. I also think I need to re program to a softer brake...:027:

Well, some things i see you replacing right now are dogbones, arms, shocktowers and shocks. You should have gone with the FT version so you have some upgrades already:)

Interesting. Mine is defineately an 18T not 18MT.

I have 3 racing shocks right now. Except the front as i broke one and went cheapo's with gpm's i had laying here. I have ti bones right now, but won't get those in until i break something!