I hope I can help ya a little

1-If the engine reeves up and the car doesn't move at first
then it could be the Slipper or the Differential, most guys that race tighten them both all the way up so they don’t slip at all.
I run mine tight/no slip at all

2- glow plug is good but you can pull the air filter off and put some in the carb too.

3- you want to see the smoke almost all the time. Most times you wont see much at idle.

4-for goofy around I use Dirt hawgs, they work well on pavement and dirt/grass.

5-you should check you engine temp after running the truck about a minute, don't wait until the engine has run for 5-6 minutes. if it too hot that will shorten the life of you engine.
I recommend if your going to be into nitro cars, buy a Raytec temp gun
the cost around $75 but they will pay for themselves in the long run

The associated engine is very tough, but try to keep it under 230
deg.s

6- the aluminum parts are mostly for show, the parts that bolt directly to the chassis are the one you want aluminum, Bulkheads, pivot blocks, servo mounts, etc. these parts have a tendency to come loose over time, you can use "loctite" on the aluminum parts and they will stay tight, you'll never see a top racer with all aluminum parts on his car, you want the car to have some "give" or else it will bend and or break.