After some tinkering, i got it to quiet it down a little, but the bottom of the impeller is a bit loose on the shaft so it has some noise still. Putting a fresh coat of petroleum Jelly on the o-rings helped a bit, i was able to get the impeller cap to sit better and the lid and valve now slide back together nice and smooth.
I found a site with replacement parts here: http://www.americanaquariumproducts.com
The impeller is only $6, but they charge you $7 to ship it ($10 s/h if you add on a set of pads).
Hopefully Aquaticfan's site is better.
Thanks for the link Evil, if those are similar to the sunsun filters (the case is dead on), the ones with the UV bulbs seem have slightly different impellers.
I still really like this filter, the only one that is doing better performance wise is my odyssea cfs4 (a.k.a jebo 838). I've had it 2-3 years now and haven't done a thing to it other than cleaning out the pads when ever i remember I still have it.
I do like the cfs4's filter pads a little better though, I've only had to replace one so far.