#1
First thing first.. how hard is it to change a pot in my guitar with only one pickup?

Second, can anyone tell me a good way to learn scales, gain speed and strength so I can start gettinig better with my guitar playing? Im thinking about buying a gripmaster.. i just dont know what level of resistance. do they help with speed and dexterity?
#2
The hardest part about replacing a pot is the soldering, so depending on how you feel about that... it's really not that hard.

Don't bother with that gripmaster. The best way to get better at playing guitar is to... play guitar. Repetition is your best friend for speed and strength.