Okay, I see what you mean, 2 ohms load by a pair of 4's in series is one ohm to each amp in the bridged circuit, although, he said they were designed for 2 ohm service, don't you think the chip will be a bit overloaded?
EDIT: Oops, I just noticed your other idea for a circuit, I rest my case as your idea with the TIP transistors would work fine as far as I can tell.