Battery drain question

[Val]

I'm really considering buying an aftermarket head unit from Pioneer (this one: https://www.pioneer-car.eu/eur/products/dmh-a340dab) which I intend to install into my Golf Mk5 (2004). Now, I already know that I need to buy a faceplate for my dashboard, but what's gotten me concerned is that I've heard that aftermarket units can cause unwanted battery drain, even when the key is out of the ignition. I've made some research and found out that this can be avoided by installing a canbus adapter/simulator or modifying the radio fuse to switched. In some cases this isn't even necessary. That's why I need to know if this adapter will be enough: https://connects2.com/Product/ProductItem/CT20VW04

[ZoliWorks]

I've had a Pioneer A3300DAB in my previous car (2009 Jetta). My unit switched off completely when I've removed the key from ignition and there was no way to use it without either having the car running or the key in ignition. I think this will be the same way.

Cheap aftermarket units can cause battery drain but even those come with a plug you can pull that makes it shut off completely the way I described above.

These units seem to work off of a "remote" wire that basically tells the unit whether it should be powered on or not. Back when I had my Chinese Android RNS 510 copy, rather than pulling the plug or having the navi on all the time, I installed a power switch onto that wire and routed it to one of the fake buttons next to the ash tray which I used to switch it on/off at will, even with the car off.