Stampede man,
Everybody has their own preferences on everything, especially when it comes to how rims look, so its hard to say. If you want to go with aluminum parts a company called Neweramodels.com makes a bunch of different aluminum goodies for the Nitro Stampede. As far as shocks are concerned, you can spend a bunch of cash on aluminum or different length shocks. But In the end if your looking for better handling; changing your springs, spring spacers, and the weight of the oil in your shocks is going to make the biggest difference.

The 360 stinger was a 2 piece aluminum exhaust, with a pipe that came off the engine that had almost a 360 degree twist before it mated with the tuned pipe. To the best of my knowledge MIP (Moore's Ideal Products) stopped making the 360 stinger, and started focusing more on the other Traxxas monster trucks. You may still be able to find one out there though. Look for one NOS (new old stock) at a hobby shop, or on ebay. Or you can try to find a used one in good condition. Honestly though, You could also install a tuned pipe from any other manufacturer, and probably get the same results as the stinger. You may also want to consider getting whats called a boost bottle. MIP may still make these for that engine. It creates a vacuum reserve that helps the engine run better, and gives you a little bit more power. Good luck, and enjoy your Stampede.