13 pin wiring for towbar

[wolter]

I just bought a VW Passat B7 Estate from 2011 and will install an aftermarket parking sensors front and rear integrated with the RNS510.
As I also want to install a tow bar in the future I thought to install a 13 pinwiring loom at the same time and install the towbar later on myself when I have decide which one I want.
Looking online for wiring looms it is very confusing. I know for sure I wont be the 7 pin with relay but a fully integrated one. However some included with parking support or not. So can anyone help wch wiring loom I need and also when have a good deal as a VW is quiet expensive.

Thanks