I can confirm that all the arms from the Mazda 6 is the exact same as the MPS. The parts are interchangeable. The only difference is that the lower control arms middle and rear have revised stiffer bushings from factory. Best to replace with Superpro etc. The front bushes from superpro for a normal 6 will fit with the MPS. Only ones that wont is the sway bar 'd' bushes.
I got the ebay arms and got a shop to press poly bushes in for me.
Also to confirm that the ball joint sleeve is ment to be in the hub. But mine was also stuck on the arms like in the picture above. Had to heat them up with a blowtorch and use a puller to pull it off the arms.