Just to update. I had one of the seals let go on my unit and it dumped half my 135 gallon tank on my basement floor. The o-ring around the lid broke. Just keep an eye on yours
There's an O-ring around the lid? I didn't see one on mine at all.
I ordered mine off
http://www.aquatraders.com/Odyssea-CFS4-Canister-Filter-p/42044.htm for $60 shipped. Got it in last week. Did the mod listed here. Glued the white and black foam pieces together with gorilla glue and letting it set over night Using a very sharp bread knife (I have an awesome Shun set with a nice VG10 bread knife) I cut about an inch away off the white and black foam pieces. The black foam I didn't cut away as much though. I left a little half inch lip from the bottom AND I didn't get where the the hollow part is from where the tube comes up from the pump. I felt that would open the foam cavity up too much and allow bypass.
I got some polyfit blanket wrap from walmart and wrapped the glued foam pieces in it. Make sure to tear a small hole where the output tube from the pump will go through. I cut a small piece for bypass as well for the top. Unlike the OP I only got a single blue pad, and not two. I got a bit away from the edge of the blue pad to let water drop down the sides as the pad isn't going to be used for filtering but diffusion of water to make it even around the polyfit blanket wrap.
I bought some 1/4" ID and 1-1/4" OD metal fender washers from home depot at 20 cents a pop. I picked up the same size neoprene washers there as well for 83 cents a pop. At 6 washers that was $6.18 for the washers. The poly fill quilt batting from walmart was only $6.94 for the size I bought.
http://www.walmart.com/ip/Poly-Fil-Extra-Loft-Quilt-Batting-81-x-96/17808679 is what I picked up. I did buy some 1" ID hose at home depot. They sold 10 foot hose for $16 and 20' hose for $30. I ended up getting the 20' hose. Why the new hose? Well the hose that come with the filter is crap right now. It's short at 2.5 feet per hose, which was not long enough for me, and I didn't like that grey vinyl material used either.
The O-rings for my filter unit were all the correct size at least. The lid I got seemed sturdy enough, but I still wanted the extra preventative precaution that the washers provide.
I had the suction holders for the intake bar and the spray bar output. They are junk on this thing. The actual spray outlet I am going to change over into a spray bar later, but what came with the filter is adequate at least for now.
Overall the price was 60 + 30 + 13 for a total cost of $103 for this filter to get it up and running how I wanted. Not bad at all compared to the competition. It seems to be working great, but I'll have to wait a few months to see how well it's filtering.