I just put in a new RR stainless steel filter with the cover the provide. I put the rubber gasket end towards the cover as explained here on this forum. With this filter / cover in I noticed my bike made a little "whistling" when reving the bike and it appeared to have a little bit (not much) of oil at the top of the cover after taking a lap or 2. My bike is a 06 450SE and it never made that sound or had oil coming out of the top of cover with the stock one. I am about to go back and just use stock cover however I wondered if anyone else had experience this or not.