I think I'm going with a 3.91 lsd. If it's to much of a difference (don't think it will be, sounds like it'll make the gears about as short as my e30's were, which I would love to have) I'll probably swap it out in a few more months for a 3.73 or 3.64, but I don't really mind the gas mileage decrease (I used to be concerned about gas mileage, but meh, life's too short) and like I said I don't mind shorter gears.