Sciuorus has updated the app-bundle of M.A.R.S.! Feel free to download and test it, if you are on this OS!
(click the image for a larger view!)
This version now contains M.A.R.S. 0.7.1 and should run on both, 64 bit and 32 bit machines under MacOSX 10.6. He is still working on support for 10.5.