My car has almost new everything for the brakes.
Rebuilt front calipers. The first thing I did was to bleed the brakes. I didn't know about the proportioning value but will try to bleed that too.
The pads have only had 200 miles use so are still bedding so hopefully there is more to come. I have to say I think my drum brakes on my 356 are as good and the disc brakes on my old 912 were better. Bad or good I could lock the wheels. I'm thinking of significantly upgrading the engine so would want more stopping power
I've read about the BMW replacement, Alfa and Volvo. The Volvo sounds like the most straightforward and effective?