[bonehead848]

I could swear there was a chart of it floating around somewhere but I cant seem to find it. They are considered 4 ohm but dip to 3 for a bit. I run them from a hk 347 and have never had any problems. If you are set on an 8 ohm design check out the tritrix here.
http://www.geocities.com/cc00541/Tritrix_pg_1.html