Dave....
I know Dave well. I met him via telephone last year. I do have the Solas Concord. I actually bought two of them with different pitch. I actually had better top end with my OEM impeller. In my info center, I have a peak speed recorded of 60mph. Now, that's not by GPS, that's by dream-o-meter.
I'm not saying your wrong about the magnum, I'm only saying that it does offer a significant change in acceleration and speed with standard horsepower motors. It's almost the same as saying to change my impeller after I've modded my engine. Of course it's gonna give me a few extra mph, that's what a change in pitch can do. I could also go with a power nozzle, after an impeller change, add a bit more. So, in the opposite direction, your doing the same, making a change for the better by a change in the pump design. Adding any type of performance part will only be better, not worse (unless you over pitch for your motors horsepower).