#1
on my 5150?

I am looking for a lighter tone instead of the thick bassy distortion my amp always doles out.

I want to play more pop/punk/alt. rock stuff than my occasional hardcore pop/metalcore

I was thinking of selling my amp, but would a tubescreamer and isp decimator make a good difference?

buying these would save me money from getting an amp head and cab instead of keeping mine

ESP EC-1000 *Vintage Black*
Orange TH30 Head
Orange PPC212-OB

DiMarzio Cables
#2
Theres always great to have with any amp even a new one. So I would say they are worth every penny. I have both and they can change your tone quite a bit for the good. Kills the noise and it will create a tighter tone.