Installed a Schmiedmann (Euro BMW specialist based in Denmark) exhaust on my euro 325i 2006 (N52B25 with 218hp). Dual pipes with one muffler and x-pipe instead of the stock dual pipes to resonator followed by one pipe to rear muffler.
I quickly put together a sloppy little video with a comparison with stock exhaust etc:
The system is built by Supersprint in Italy for Schmiedmann. I think it's only produced after ordering so I think I bought the last one in stock in Denmark via Schmiedmann Sweden. Link to product:
https://www.schmiedmann.com/en/bmw-e...=SCM9091R276NR