Im looking for some information on upgrading my exhaust system on my '69 American Champion Citabria. Im new on here, so forgive me if there is already a thread i did not see that already answers my questions. I have a 150hp lycoming O320 and i am not having much luck finding an exuast that is offered that will improve performance from original for this model plane. There are lots of options for guys with cubs or similar that run the same engine, but not when it is hung on a citabria. Any direction would be appreciated. Thanks!