It sounds like a pair of 27-spline Longs would be the south end of a north bound cat, but I can understand $400 being too much money. Another option would be to have Bobby Long (www.toyotasuperaxles.com) heat treat and cryo freeze your birfs for $65 each. It might be the cheapest option a possibly be about as strong as the MC-05 (I know nothing about them). Just an idea.
Not a bad idea, but I'd hafta pay shipping to and fro plus the $65, or $80 plus shipping one way for new, and if I remember right Marlins have a little more metal to em than stock. Also, there's a guy runnin outa the corner of my buddies shop who has a cryo setup, and I thought about doing that, but I'd almost rather get the um05s and have him treat them maybe, but I'd hafta check with Marlin first and see what they think.