Here’s a very professional article by Gustave Stroes detailing his installation of a Burns Stainless Y-pipe on his BMW E30 M3. Lots of great pictures.
For one of the best studies you’ll ever see on tuned exhaust system phenomena, with extremely informative gas pressure graphs from measurements on a Lycoming 4 cylinder engine, check out: Aircraft Exhaust Systems IV and The EPG and Aircraft Exhuast systems by Brien A. Seeley and Ed Vetter. You need the Adobe Acrobat reader to view it.
