we all know that evo7 front callipers will fit on are 300s but had anyone fitted the rear evo7 brakes ?

Iirc they don't or are a nightmare to fit. If you want matching brembos you can match them up with a particular scooby rear calliper, there is some suggestion it's no better than the zed one. From what I've read the Evo brembos with stock rears and the bm57 master cylinder should be bang on.

I see do you need the bm57 master cylinder to use the front evo brakes> will it work with the the stock tt master

I have the evo calipers at front and stock tt rears and it feels very good. Much better then stock fronts.

I was looking at using k sport on the front I wonder is the evo callipers would be as powerful

I got evo brembo's up front and kept the same master cylinder

how much better over the stock tt callipers were they

I really felt a difference mate, If you can wait a week Ill be putting my callipers back on (2nd Zed) I'll take some comparison shots, but confidence wise, loads better.