Agree! With the rectangular filters, I use a little synthetic grease on the gasket to enhance the seal to the airbox. It's also a good idea to make sure all the intake connections are sealed properly. I had a leak on the intake of my 98 Chevy's 6.5 Diesel that resulted in Si levels of 45ppm. The Turbo intake had a resonator tube that was connected with a small rubber hose. The OE connection was just a press fit with no clamp.. I added a clamp and the Si level went to the single digits on the next UOA. I also recently sealed the filter minder on my Duramax Diesel with RTV. It was also just a press fit into a gromet on the clean side of the air box.
