Nice job! Looks like they're in a good place to protect the rads and engine covers. Any pics of the slider base where it faces the engine bolt? Just curious.
And a suggestion for Radar, if you wish to make more of these as a kit, I would buy extra engine bolts and tap them, then include them and their price in the kit. It makes it more appealing to people that way, as all they'd have to do is spend $$, without having to track down a machine shop and then wait for them to do the job.
And one more, maybe offer the "centering plugs" with a deposit, so buyers could return them, and you wouldn't have to make so many?
All that said, I might buy a set, if you're making them...