If you're talking about the cross-member that connects the rocker panel to the center tunnel, I wouldn't hack that out unless you're going to replace it with something structural.
If you want the seat to be adjustable, you can strip a stock seat-base and attack it with a hacksaw (I'm high-tech here, and used a Porta-Band), then weld up some square tubing to what remains of the base and tag on some 'ears' to attach to the seat. Voilá ! Adjustable Kirkey Intermediate seat in a VW !