This post is a little behind chronologically. The Maryhill Hill Climb event required an on-board fire extinguisher. I cut out and bent a mounting bracket from aluminum and bolted it down to the cross rail in front of the passenger seat using rivet-nuts. Easy reach for the driver, doesn’t interfere with the passenger seating, and weight is nice and low.
I also added a spring loaded stopper for my oil dipstick as it popped out the last time I was at the Ridge Motorsports Park and made a real mess.