Regarding noise, Tekno vehicles often have a unique sound to them. That being said, I've had some louder and some softer. The thing that most interested me though, was when I switched motors a few times...it DRASTICALLY changed the sound of the vehicle, despite all the motors being pretty quiet outside of the vehicle and using the same pinion. That was a while ago, but case in point, don't worry about the vehicle being loud unless you just don't like it loud. For trying to silence anything that is chassis related, use a little more grease on the ring gears in the front/back, and put a small O ring inside the front and rear couplers and center diff out drives. The warning on the O rings is that this could make things worse for bending your center shafts in a horrific crash, especially if you don't run the chassis braces.
In any case though, if you know mesh is good, the loud sound isn't a problem.