. . . unless you don't get the (separate) O-ring gasket lined up properly on the canister filter cartridge on your 300D. The O-ring is at the top of the filter housing, so I didn't realize it wasn't in correctly until I fired up the engine. It had in fact slipped completely down around the filter, leaving no seal whatsoever.
So this was the sight that greeted me through the windshield as I backed up the slope thinking I was finished. My own little Exxon Valdez. Pulled it back down, re-installed the O-ring properly. Now for some Simple Green and absorbent compound.
Just goes to show that a brilliantly conceived one-case tool kit does no good if you don't use the tools contained therein properly.