So my haas sl-30 is a vdi turret. The boring bar holders only hold up to 3" of a boring bar. I have been using steel bars up till now and just have to saw the bars down to get them so don't hang out of the holder so much.

Now I've got a couple carbide bars that are just too long is there any suggestions on cutting down carbide bars? Can I just use my bimetallic bandsaw or is there a special way to cut them down?

Your bandsaw won't touch carbide, but it would be fun to watch! You need to use an abrasive cut off saw. Even a zip disk will due.