Well if you would spend that kind of money on a pre/pro, you'd have alot of options!
Do you mind mix-and-matching? If so, yes, you could do something like an AVM20/Parasound HCA2200 combo. Or, you could stay with the Parasound 2500u preamp and keep it in the family. However, I wuold probably keep it all Anthem for the cosmetics and chemistry of it!
Alot of options indeed, as you can consider at your budget, Class amp and pre/pro, Sunfire combo, Aragon combo, all the way down to Outlaw, and still have good sonics! YEah, if it were me, I'd try the AVM20(partially because I'm interested in what it might sound like), and maybe try the amp. You can always compare with others, and sell what you don't want. Good luck