If you were happy with the performance ... stay with what you have (although if you go from a Berk impeller to an aggressor you need to drop a size. Aggressor runs the blades all the way to the front edge which makes it a cut size larger in water flow. (An Aggressor B matches behavior of a Berk A) If you want lower RPM (by something like 500) and a better holeshot then size up a cut, or a half-cut (A-B) to drop 200 to 250 or so.
According to Jet Boat Perf Calculator, 650 HP spins a Berk B at 6223 RPM.
I'd go to an A personally, Drops top RPM to 5900 Will drop your speed likely tho.
You can save 300 bucks by going Mag-Bronze if you want. I am considering it.