What are the true benefits of this? did a little price comparison on realoem and there is a HUGE difference in price. I have seen in someone's 545i sig that they have upgraded their brakes. Would this upgrade be overkill or is there a more cost effective way for a bbk? I would imagine there aren't any clearance issues as well...

 

Per some member mentioned that it's mostly for the look value than performance unless you bring your car to the track.
How fast can you go and stop? Do you make sudden stop from 80-100mph often? If yes, then I think it might worth it.
How strong is non-M5 master brake cylinder compared to M5? Why M5 master cylinder is different from regular E60? That's because it must be more powerful to push those 4 brake lines. Does regular E60 master cylinder provide sufficient breaking power to M5 brake kit like M5 master cylinder?

 

If where do you live you have a good grip asphalt, M5 brakes are better than 545i brakes .
On track the difference is really huge, both as breaking power and as fading .

Some weeks ago I was about at 130 kmh in the city ... Traffic light became red ... I breaked hardly and I was surpriced about new brakes .