The selectable units are still $280 delivered to the continental US. Selling prices on the internet have gone down a bit, but cost has remained the same. I started with a very low price so, that can't change. I am not doing this for profit.

The new selectable version does allow adjustability, you can select off, mild improvement or full (or race mode). When I drive, it stays on full, however when my wife drives it, the switch is off.

Definitely getting less wear out of the rear tires, but it is sooooo much fun, it is worth it.