In think so (I have the gx1)
Then yes.
The 14-150 (28-300 equivalent, around $600) is the most practical "big" zoom, as in it'll never have to leave your camera, since it covers everything from wide angle to telephoto.
The 45-150 (90-300 eqiv.) is the same at the long end, but it starts out links already. That means you'd constantly have to switch it with something like a 14-42. It's much cheaper at around $200. The 45-200 is similar but longer for an extra $80.