I have heard that all the wiring is there, You need to find the connectors under the seats & in the console, You also need to get the switches that fit in the console. :tu:
Ive seen the switches on eBay.
I can't speak for the 170, but for the 171 a lot of the seat bottom heaters fail, like mine, due to broken mesh heater wires. In other words get some assurance that they actually work when you make a purchase.