You could put the bottle in the rear spare tire well and make a board with carpet over it. The soloneids (sp?) can be hid in several places. If you get the kit that has a plate that goes up next to the throttle body you can do several things. The lines going to the intake can be hidden under that scrunchy electrical sheathing or inside a big rubber line so it looks like either a electrical connection or vaccum line running off of the throttle body !

I will not mention why I know this....