I made an aluminium plate that bolts into the center console bolt holes. The extinguisher brackets mount to the plate. I did it this way because
1) It uses original holes. No drilling or screwing required
2) Didn't want to lose the ability to move passenger seat forward
3) For track days (and safety in the event of a crash) screwing a couple of self tappers into the center console is not strong enough.
Can't help but think that the center console was deliberately designed to accommodate a fire extinguisher, perfect fit, and the little recess for the trigger.