Heh, you see, I have a suggestion, and a way to go around the problem with the bs missile immunity. Test this: get a new freelancer copy, install disco on it, and alter the sunslayer. Put 40k damage on it, then shoot a couple of bs with those sunslayers. They will do damage. It have been tested and proved to me by a friend (not naming, because i don't want to upset anyone:P). If I still have the pics, I will add them to this post.
EDIT: the test involved talarca cruisers, and sunslayers with altered damage. nothing else, nothing more.
I have found other things which would improve the gameplay, send a PM if you wanna hear them:)