The Angus Young bridge humbucker goes for around $161 US, but you would also want to replace the neck with a humbucker. You would definitely be hard pressed to get the AC/DC sound with the P-90's, but you can come close enough with the HB's that come stock in the standard. By the time you upgraded you would almost have the same amount of money tied up in it as you would the standard. That being said, I would go with the standard if the AC/DC sound is your main concern. Good luck and enjoy which ever you decide on.