I am looking for a straightpipe, downpipe, and blowoff valve for my 2012 Mini Cooper Coutrynman S. Can anyone help?

 

Have you seen the post about downpipes in the Countryman > Modifications > Cooper S Drivetrain forum? It's the second latest post. You can also search the forum or on Google and get results. At times Google will show you more relevant results, even links from this forum.

A blow off valve vented to the atmosphere causes a car to run rich on vehicles with an airflow sensor. Why do you want that?