Cam Shaft question

Will changing the cam shaft on my scoot make it go any faster?

Is it legal to change your cam shaft?

If I do change my cam shaft, what type should I get? (I don’t want to buy the same thing they are going to take out)

I drive a 125 cc Yamaha Breeze. I am not sure you can change the cam shaft on them but if you can let me know. Cheers