I just try to positivily participate.
I got no qualms with alivio, but I don't ride hardcore DH or extreme freeride. Anything intermediate or cross country, alivio should be perfectly fine. (It set up prefectly fine for me with no problem.)
And the mustang II came with a 4cyl option, so a 4cyl mustang def does exist as compared to a sportscar dunebuggy.