Jeez Michael!  Thats a ton of flow!  I also am going to be bumping up my flow quite a bit.  I've been looking at some different powerheads, and have been weighing my options.  I have only ran Korallias so far, and am thinking of trying something different.  I've been looking at a new CoralVue Dual Prop powerhead thats rated at 1500gph, and kind of split between 2 Korallia type outlets.  Also, I've been thinking about just adding 2 Taam Seio Prop powerheads that already have a magnetic, adjustable mount and I'd be adding 2 of the 1000gph ones.  That would bring my total in tank flow up to 3200gph with the Seio pumps, or about 2800gph with the Coralvue pump.  Also, once I finish my sump I'll be splitting the return and adding 2 eductors to blast some water behind the rocks.  A Mag-5 will most likely be used as return pump, which is rated at 500gph at 5'.  Hopefully the eductors will add a bit of flow, but I've never had any experiance with these.