This is pretty good work, but I don't think you can expect a 10mpg increase if you're not willing to do some EOC and other techniques. You can get away with it on the highway if you are willing to at least put it in neutral instead. Any combination of the
mods I recently did gave me about a 10mpg increase from my previous norm, but I also pay very close attention to techniques while I'm driving. You might see a 5mpg or so increase, not to be a naysayer. More power to you if you can get an increase of 10. I don't know how well you can do with an AWD car either (pretty much all subies except for a few like the justy are AWD, right?) I'd suggest doing what I may end up doing, which is making a little wiper spoiler so the wipers don't create any drag - I'm currently running with only the driver side wiper, which I'm perfectly comfortable with.
As for the mirror thing, you may want to opt for the driver's side, folded in setting. Many state laws require that mirror there, but don't say anything explicit about it being folded in, so if you get stopped by smokey just apologize and fold it back out. You could even make a nice little fairing for when it's folded in like MetroMPG has (although I believe subie mirrors fold in more gracefully):
