Clarion m303 or m309

Does anyone have any experience with either of these head units? I am going to replace mine and add an mw1 remote with it at the stern.

What are the advantages and disadvantages of both? I think the 303 has the USB connection on the back of the head which is someone of a pain.

Also has anyone installed a mw1 on a 98 outback? I would like to add it at the back but not sure if I cut in the back, I will have enough room with the gas tank there.

Any insight would be greatly appreciated.