UPDATE: This has been sold! Sold my 2006 Prius recently and ripped out the (functional) Coastal Tech EV Switch. Should work fine in any 2004-2009 Prius. The orange wire has a small bit of insulation damaged up by the pin from stuffing it in the connector originally. Never had any issues because of this, though, and there's no chance of it shorting to anything around it. I used this thing during every drive to enhance MPG (many tanks in the mid-to-high 60's!). Includes the original wire taps. I couldn't find the printed instructions, but I have a PDF of it. Yours for $35 including shipping!
The smaller and more flexible your hands, the better . I've installed three of them in my day (plus uninstalling this one, of course). The only tools needed are a small pair of pliers and a tiny flathead screwdriver (or similar device).
Thanks for the PDF. It does look like I can handle this install. I'll take it at your price, shipped. PayPal? PM me with your payment details.
Your 2010 has an EV Mode switch built-in from the factory. Admittedly, they made it much more limited in the Gen3, but at least you don't have to mod the car to get it!