i did that last feb
mostly because the 9800 pros are mini heaters and I didnt want my cpu to melt
edit also I nabbed a pair of needle nosed plaiers before I did my mod
it went great except I totally pulled of the plastic housing the fan power cord plugs into (right off the mainboard) luckily it stuck back on no problem
did u use the temp sensor?
me I installed the fan control panel on the back of the case and cranked it too 5500 rpms and havent looked back