If you're running a DC with the 25 Kohler and have the Thompson filter system you should check the seal or lack-there-of between the aluminum Kohler air filter housing and it's baseplate. Since it has been so dry here and I am grinding up leaves I decided to pull my entire filter system apart to check for dust and I found a lot of really small dust inside the Kohler filter housing. It has been leaking past the non-seal between the housing and the baseplate. A trip to the hardware store netted me a 12" by 12" peice of 1/16" thick rubber. I cut myself a nice rubber seal for the bottom of the housing. Eric, if you read this you may want to pass this along to Art when you see him this week. The best air filters in the world don't do a lick of good if dust is getting by them.