every controller. ...... 4band?
 

well i was just reversing my old charger mod on my controller becasue i put my stock battery back in and i was just lookin at the controller PCB ( or wateva ) wen i noticed the frequency chip ( band , crystal ) that i remember from wen i used to race 1/10 scale rc. mine said 27mhz on it and was like glued in but i was thinking ... if i was ti replace this with a 57mhz crystal ( i dont even no if they exist by themselves ) would my controller become 57mhz?

It is possible to replace the crystal. In fact, it's possible replace the ocilator in some larger R/C controllers with the one from the Bit and have it work.

hmm interesting. has any1 heard of bit char q? is so if i got a bit char q and replaced the crystal from my bit controller into my 1/10 rc controller would it give my bit proportional speed? wid out using a very poo digi q controller

Unfortunately it doesn't work that way. The controller isn't what determines the speed, the car is. You won't get anymore features out of a new controller but if you have one that is more comfortable etc. you may be able to use it.

Actually, no, you can't just put in a different band crystal into your controller without having to tune it. If you have a 1/10th scale R/C car, try putting in a 72Mhz crystal into a 27Mhz controller, or vice-versa, and you'll see exactly what I'm talking about.