It's not that big of a deal. As mentioned, you can get the 450 psi output from Crossfire or NitroDuck and be quite well set. I currently use the 800 psi output Crossfire into a WDP reg on my Cocker with no problems whatsoever, and I think such would work well with a Bushy as well. Maxflow inlines are expensive but VERY VERY effective. You could just settle for the stock reg if ya still have it and use the 450 psi output screw in, as that's what they were made for in the first place.