[quote name='1970' timestamp='1385399670' post='2287766']
....The wattage doubles @ 4ohms....
[/quote]
But the volume won't.
Is this just a bit of gas or do you really need more volume?
If you're current rig is underpowered then the most cost effective option is to add a second cab. Going to a 4 ohm cab will only work if it contains more speakers, like a 410. But, IMO, 2 Compacts will be better because they are practically as loud and much lighter.
Techy stuff is not my forte.... but I believe the increase in volume between 8 ohms and 4 ohms is about 3 db and that's a very small number to your ears, especially in a noisy band. Adding a second 8 ohm cab will give you an extra 6db, which is a difference in volume that you [i]will[/i] hear and, because you're moving much more air, will give you better tone.
I know someone using 2 Compacts and they get a great sound.
I’d check out the Compacts in the FS section.