Thanks, I'll take a look at the link! So you'd recommend I just run a 4 ohm extension then?
Really the best option is to convert your combo to 8 ohm and then add another 12" 8 ohm extension. The drivers can't really handle the power the WA puts out at 2 ohms anyways.
I personally preferred the sound of the 4 ohm driver in the scout combo when I A/B'd them but the difference was subtle. I have two 4 ohm cabs and the amp runs fine on loud rock gigs even with a upgraded quieter fan that doesn't quite move as much air as the stock fan.