Fumes constantly. Whenever any window is open and I peg the boost gauge. Even when the car was new I'd get cat stench at times inside. Anyone else suffer from this? I read it all the time in here. This worked so good for me so I had to share it. The only time I smell my exhaust now is when I get out. Fumes are gone. Almost 100%.
Go in the trunk and find these vents/exhausters. One on both sides behind the trunk liner. To my knowledge, their main purpose is to vent the cabin when the doors shut. Seal the bastards off. I used a sheet of asphalt/dynamat type of material and just layed it over the opening. No more passengers bitching about headaches too!