Technically, there is no "Bass X3"

. There's just the Pod X3 or X3 live (which I'll be upgrading too also) which can be used equally well for both bass and guitar. I'd go for the X3, because not only do you have the guitar models at your disposal in case you wish to play guitar, but sometimes you can get interesting tones on bass out of the non-bass patches. If you have the extra $100 to go for the live version of the X3, I'd do that if I were you.