I have SLK-947U and I get 38-39 idle (48-49C under load). THis will depend on room temps and air flow in the case. I tried two fans Panaflow 92mm high speed and SilentCat from Thermaltake. They seem to perform about the same from temp point of view. SilentCat is queter at 12v (full speed), then Panaflow. Fan speed controler (say at about 9v) can lower Panaflow noise drammatically, while SilentCat is almost always stays quet (relatively small difference between 12v and 7v). Lowering ether fan's speed did not seem to increase temps (maybe by few degrees, but iit varies by that much anyway from day to day). I also have two 80mm fans blowing air out of the case (SVC brand fans). Even if I only use one case fan, I get pretty much same temps. I tried butting as many as 5 fans in my case (it can have up to seven) and it only decrease temps by a little. It was not enough for me to justify higher noise. Having more fans might help with load temps, but I do not mind having 49C.
Ohh and my SilentCat is 92mm.