If you want to upgrade the x96, it is an Eagle unit. There are several gurus on here that can give you guidance. As noted elsewhere, the 640c GPS unit plugs right in.
So Todd, did you get the boat in the water Saturday? any pictures yet? I brought mine sight unseen and it's driving me crazy. My last new boat was a nitro back in 95, so I'm not worried about the craftsmanship, just never seen any good pictures except what KLSU has in his library of the Z7's.