[mcl fabrication]

hello maybe I can help. Tamiya make a euro version for that truck that has the authentic Scania or euro truck sound. I personally use the built in speed control only for easy hook up and space management. Some people use a external speed control when they require more power (amps or voltage) than what the unit can push. I use my trucks to haul heavy loads (dirt, rocks and trailer. If you need more power than that then you would go external. There are other much cheaper sound units on the market, just no lights. That's another kit all entirely. In the cheaper kit you can program in a few different engine sound and brake sounds and horn also. So in all what's best is usually what's best for your pocket. Tamiya's unit is basically convenience in box instead of a unit for every action you wish to do with your truck. And all can be controlled from your radio.