So, some advice for what it's worth. This is not aimed at you--just a general comment. I realize modifying/upgrading a nitro vehicle is half the fun...but I see a lot of guys upgrade just to upgrade. I used to do it as well. This is why most of us chose nitro--to wrench! In fact, sometimes I HOPE parts break so I can upgrade--but have learned sometimes stock parts will last gallons and gallons.
You'll often here people reference a specific vehicle and say "alum rear hubs are a must" or "don't race it until you get alum shock caps", etc.
Take a re-active approach to this. In other words, know why you are upgrading before doing so. Understand the problem (that you have experienced with it first hand) and how you want to solve it.
Think in terms of this: some parts will wear down over time. If stock are inexpensive and you get good mileage out of that part...just stay on top of it and switch out as needed. Let's use bearing inserts as an example. Stock plastic are $3.00 and alum ones are $20.00 Stock ones will last 4-5 gallons before showing any wear. I'm sticking with stock and switching out as needed. This also keeps the vehicle lighter.
On the other hand you have impact parts. These are ones that will not wear down, but will "break" if it takes a bad hit. Hinge pins as an example. They could last forever, or break the first time you run. If you bend one, look to uprade to a stronger material. If someone tells you "HD hinge pins are a MUST..." duly note it, but wait until you break one before upgrading.
Other than that...just keep all parts like new and smooth as silk. ;-)