I recently put an order in for two rena xp3's for $109, which is a GREAT deal. However, they will be on back order till 12/29/08. I also found out that the xp4 is 21" to the top of the hose barb's and I have 22.5 inches of clearance in my stand. So now I'm seriously contemplating canceling my order and finding some cheap xp4's. The thing is the xp3's are sooo cheap and I"m worried that I'll end up paying $200 more for the xp4's and I'm not sure if I wanna make that move. Sorta stuck here "Awesome deal vs. Great filtration".