"Ditch everything" might not be needed, but you're talking about a near complete system revamp anyway. I mean, with new pump, new fans, new hoses, you're halfway there. A heatercore and mcw6000 waterblock will only run you another $60, and the difference in performance is rather significant. Those 1/4" ID hoses and 90 degree bends inside the kit hurt flow lots, and I'm pretty sure the koolance waterblock itself isn't very good (def. not a cascade or mcw6000).
Honestly, what I'd suggest is keeping the exos and using it as a secondary loop to cool hard drives, north bridge, graphics card, etc. It would work pretty well for that, and there's no sense letting the blocks go to waste if you've got 'em. I had the guts of one of the earlier koolance systems working in this capacity until I decided to cannibilize 'em for a chiller project. Odds are with a fair sized case your buddy can fit in a heatercore and pump in addition to the exos stuff. Plus this way you don't have to jack with the exos itself.
at the
koolance website, btw. The bluuuu LEDs are apparently a major selling point.