Yes mate a milltek will really change the exhaust note. Much deeper and racier tone. Really compliments the car. Are you changing the down pipe also as that makes a big difference. I have a non res decat on my gti and i love the sound. Only
Down side is you have to replace the cat for mot but well worth it in my opinion. As for the brakes just go r32 with a decent set of pads, more than capable for fast road use.