It sounds and looks good to me and is extremely light. Would it be possible to pair it with a GK MB200 head as the only cab? Then, I'd have a portable rig less than 20 lbs. I've never used an extension cab before, so I don't know the difference between a bass cab and an extension cab.
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2004 Fender USA Precision (Butterscotch, maple)
2005 Geddy Neck + '62 RI J Body (3TSB)
It's the same thing, and it'll work fine. Just be aware, volume comes from multiple speakers, so your head plus 1x12 rig won't be any louder than a comparable combo amp. If it's not loud enough, add more spkrs.