All good mate, a friend of mine runs a mazda/ford wreckers here in Aus. I have a set of 2006 Mazda 6 MPS brakes (twin piston front) with all brackets discs etc for fitment sitting aside for me. Its only going to cost me $550 for front and rear. Then I need to purchase new slotted discs and pads front and rear. I can get those through work so not a big deal. I will probably go with bendix street/track pads and K2 discs.Good luck trying to find MS6 brakes. I've tried lots of different sources saying they have the MS6 calipers, and none do. MS6 calipers are very much different from the standard M6 caliper. I took my front 2003 M6 calipers and compared them to a guy's MS6 and there's a lot different. If you want MS6 brakes, pull them off a MS6 or get them through the dealership parts department. Don't trust the inventory at other sites like Rock Auto, Advanced Auto, O'Riley's, etc..
My main concern is that I have heard that the brakes on an Australian M6 are different to the brakes on a US spec M6. Hence I am worried that they won't be the same bolt on fitment.
In regards to extending the Handbrake (Ebrake) cable, I have all the stuff in the workshop to do that so that side of things is easy enough also.