Probably dumb exhaust question; will ask anyways. Exhaust fumes in car with windows up IF you stand on it. ('05, R53) I have taken off heat shields, car up high on jack stands, plugged tail pipe (standard muffler shop practice....) for 5 seconds while 2nd person looks/listens for leaks. Got auto stethoscope for air leaks, still cannot find. With cabin exhaust smell (only when stand on it that I notice, maybe "slow death" at normal speeds..... ) most likely manifold cracked where 4 into 2/1? or gasket? or? R53 history of manifold issues? Hate to pull apart or spend money if not pretty sure most likely the issue.... Thanks for any help. (Rest of exhaust system, ditto on can detect no leaks) Is original equipment and car is modded, used for autocross.

If go aftermarket header/manifold want to make sure will not throw codes. Plus can keep standard heat shield. Flashpoint header from Way good choice?

 

If you believe it's an exhaust leak then check by the cat. It's not uncommon for it to crack by the header/cat. From the image below, the failure area is by the mesh where it connects to the header. I'd also suggest maybe checking for oil leaks that might be making their way onto the exhaust and therefore burning off when making contact to cause a smell inside the cabin.

http://www.pelicanparts.com/techarti...eplacement.htm

 

Thanks for the help, Pelican Parts. No oil leaks and is exhaust smell rather than burning oil. Will keep hunting and checking again where you suggested.