couple weeks after the event, but some may find it interesting nonetheless:
I had BMW's M-performance power and sound kit fitted by my local dealer. A remap and valved cat-back exhaust, all covered by BMW warranty, and also got the matching diffuser as the exhaust protrudes a tiny bit more and it looks like a wheelbarrow without it
. Plus as mineral grey almost exactly matches the m-sport diffuser colour, it kinda looked like an SE before from behind
Takes car from 325bhp to over 360, plus a shed load more torque (and a rather incredible noise with the valves open!)
before:
after:
With the valves open it is essentially a straight through exhaust as you can see from the underworkings
. Very glad of the valves for driving back into my village / onto my driveway etc, as whilst it does sound fantastic it is rather loud with them open and would be unlivable if they were always open.
It really has changed the way the engine delivers its power, way more than the headline figure increase. It's far more urgent from ~2k rpm now, yet still wants to rev to the redline. The B58 really is a fantastic engine.