i just got some sebile magic swimmers and a spro bbz-1 shad. I was wondering how these do in salt water. I was wondering if it was bad for the joins, if theyll rust out or not.

The original Magic Swimmers were made for saltwater use, so I'm pretty sure that you're good with them.  No clue on the BBZ.  I'd be sure to rinse whatever you use in freshwater as soon as possible once you're off the water...

if you change baits on the water, or when your headed back home on the boat ride or the car ride, take the lures and hooks that you used in saltwater that day and toss them into the melted ice in the bottom of  your cooler. tada!!! clean as a whistle.