Other things you may do.... I don't know how stock your truck is, so here goes.
If your wheels are stock, change them hpi gt5 wheels are bad about spinning the hexes out of them. read up on some threads about removing tires if they're stock. it can be a pain, so take your time.
With the tires off run two or three layers of duct tape on the inside of the TIRES. This will stiffen them up and make them less prone to "ballooning" (when you cut into a turn and the tire swells up to twice its normal size due to the geforce) It will save your tires in the long run. When you're there, replace the foams too with firmer ones.
If you do end up changing the wheels, I'd recommend RPM wide offset wheels, they really help it against rollovers.
Secondly I'd get a rotostart for it, the savage 21 comes stock with a pull start and that engine can become a PITA to turn over. Rotostarts are well worth the money, just be careful with running it too long. Remember 5 seconds at a time.
check the gear mesh and make sure it isn't too tight/too loose. You don't want to end your fun quickly by burning up the spur gear.
Third, a hump pack and failsafe is a must for that truck. The failsafe protects your investment, while the hump pack keeps you running longer and gives you better response out of your radio.
The spider mod and cam-type servo saver is definitly in the works for your new truck. They even include them free in the 25 models.
If you're planning to bash, I'd also recommend a new PROLINE body, they are very thick and really help to protect what you have (and you can paint it uniquely)
If the springs are stock, you should change them out to the black, silver, or purple springs to stiffen it up, and reduce body roll.
If they're not there already, put about four wire ties on the head of the engine to protect it if your head when/if you roll it over. Especially on cement.
You may want to also take the time to loctite every bolt that goes into metal. It helps them from backing out from vibrations, jumping, ect. and reduces radio interference.
When you do all of these things, you will find yourself not needing to work on your truck very often. Just keep it oiled and all the bolts tight and that truck will treat you good. And, DON'T FORGET keep it clean and use that After Run Oil.
:spit: