ACR's are 40 a piece, the harness is 50. If his heads are already prepped for them I don't even think he has to take off his heads, only the tank. I don't think he stated what heads he has, stock or otherwise. I had mine installed a few years back as well and I am very glad I did too.
Well, assuming he has the stock heads then they definitely need to come off to be properly machined for the CR's.