Hey,
My 2 cents.
Doug and Tony are right and very informative. I would like to make it perfectly clear that your current wire selection is okay. You shouldn't walk away wishing you had the other wire because it won't make any difference to YOU in YOUR system. If you listen to your system and are happy with the sound, Great! If you are unhappy, changing the wire won't make it better. There are so many factors that go into good sound that you shouldn't stress over that wire. Doug explained the wire calculations well but you must remember that he is at a more professional level. Your amp probably uses a DC to DC converter and at MAX volume you could end up with output clipping if you don't have the proper voltage. It may also affect filter characteristics if this stage is not regulated well. These are problems that you will probably never run in to.

What I'm trying to say is take the money you save on that outrageously priced 4 gauge wire, get a cold soda, some new music and enjoy your awsome new system!

Alex Lear