I just got a new Deluxe like yours. Saw that the Mark III isn't available for the '08 FSTLN, so was thinking about the Mark IV. Was it hard to install? Looks like it's awfully close to the rear brake pedal. Does that pedal get in the way?
I went with the Mark IIIs because I have extended reach brake&shifter levers and extended floorboards on my Fat Boy. the Mark IVs wouldn't work. even then, I had to drill several newholes in the floorboards to make them fit.