they have different cores which allows them to have an overall different camber. And both side walls, although ABS, vary in tortional rigidity. The FS's side wall have more support at the tips, when as the BC's side wall provide more stability under the boot. Also the laminent on the BC is made of only 2 main components of fiber glass, where as the FS is made up of 8 thinner layers of softer fiber glass, alowing it pop better off jumps, where as the BC's laminant make up lets it me stiff fo powder skiing.
okay i just made 100% of that up, but i think it sounds pretty good
go buy 'to whom it may concern'
So what?..... So lets dance!