I use the cat whiskers mounted under the tail. That way it doesn't get kicked and isn't an eyesore. I've installed them on both the -6 and -8 with great results.
http://www.aircraftspruce.com/catalog/avpages/ramiav525.php?clickkey=15410
not cheapest, but hard to cheap out on IFR when you NEED an antenna that will function dependably.