I have a Kenwood KAC-8405 amp and it says that it can power 60 watts RMS x 4 at 4 ohms (90 watts x 4 at 2 ohms). How do I get it to power 90 watts at 2 ohms? I have 2 JBL GTO938 (I think) 6x9's that can do 100 watts RMS each.