One the early-2008 Mac Pro systems, the two upper most open slots (#3 and #4) are 4x slots, either one is perfect for the KONA card.
The lowest open slot (#2) is a PCIe 2.0 16x slot. They say it is will work with PCIe 1.0 and 2.0 cards. This is where you could put your disk array card, most of them are 8x cards.
I have not been able to confirm this but these slots may not be configurable as in the past.
Fred
The Troupe – Modern Media Design & Production