The I6 dyno is with the dual exhaust.

 

This really throws a wrench into which exhaust I'm going to get now...

How's the sound, both exterior and interior, compared to stock?

 

The quad system is TUV approved. It is deeper than stock and slightly louder. It is noticeable without being intrusive!

 

how much for quads for 545i shipped to 94015? when you say the tips needs to be shorten to be fitted onto OEM m5 bumper, how would i go about adjusting it to fit? Would i need to cut the right side?

 

Yes. The right side connecting pipe will need to be shortened.

 

Both systems are in stock.

 

Any one has picture of the Quad setup with OEM Bumper cut out?

 

Voila With 2.99" straight cut tips.

 

I might be looking for an exhaust, specifically a single sided one for the 535xi. As you have said there are some slight modifications to make it fit, but do those modifications effect performance at all? I'm just asking because I bought a magnaflow muffler and my shop advised me not to install because in order to make it fit, it would actually be more restrictive than the stock muffler. Is there a dyno for single sided 535xi? I'm not interested in a quad system. Thanks!

 

No dyno for the 535i/xi. I would assume you bought a system that had too small of an inlet. Our V8 system features a 3" (2.9 for 545i with adapter), the shape of the inlet pipe is slightly oval on the 535i, this is what will need to be modified on our V8 system.