Sandy - Most cars with separate turn signal and brake light bulbs require a 'converter box' to operate with standard trailer lights, since on the trailer there is only one bulb which does both the turn signal function and the brake light function and those are separate bulbs (or LED's in our case) on the car. I suspect this was the 'expensive' box they used in your installation. The converter boxes are available on eBay for about $30. I have them installed on my other cars and they work great
The Torklift website says "Notching of lower plastic is required" - Did you have to cut the lower rear bumper plastic for your install?
I'm actually a little hesitant to install a hitch on our iMiEV - Our little Mazda wagon is getting so little use, I think it enjoys getting out in the sunshine every couple months when we need to take the trailer to Lowes to pick up building supplies