We looked at the 2nd car kits when we couldn't decide which Cherokee to tow, lots of $$ for a little convenience.
What I did was take some 3 pin connectors for the brake signal from the toad, 12V + and - and wire them into each toad and tuck the toad end under the center console, then wired one of the male ends onto the transmitter for the Even Brake. Now I just move the unit from one car to the next (the Wrangler got setup later) and plug in the 3-pin, situate and plug in the breakaway, install the "box" hook up the 7 pin mounted in the bumper run the test and go. I also use the same unit flat towing behind the truck and camper, the unit doesn't care where it is.
Have fun
Dave
'99 Alpine 36SDS/8.3 ISC 330 Cummins
Or
'05 Lance 845
'06 Super duty SC/SB 6.0
Upgrades include: StabilLoads, Air Bags & Timbrens,Swaybars
Usually towing an '01 Wrangler, lifted/locked on 35"s or a mildly built '98 Cherokee on 33"s (only one locker)