I could have used the decoder, yes. But my preference is to go OEM where possible. From what I remember the kits with decoders were around $500. I paid a little less than that for the Audi A4 RGB kit (with harnesses). The decoder kits with trim pieces were another $200-ish and I paid about that for used door trim on eBay (I had to do full replacement, my silver Golf trim doesn't have the strips). I figured somewhere around $7-800 (not including my labor of course). So I figured decoder and non-OEM lights or OEM RGB's and facelift BCM were about the same cost.
Going through the process of "converting" to all adaptations for the new BCM was fun, to me. There are also some things you can do with OEM (BCM controlled) RGB lights like variable brightness for different zones, variable timing for zones so it looks like the car is "powering up" (you can have footwells, then center console, then door, then dash, etc.), different brightness for different conditions (for instance door lighting going full bright when that door is opened). There's also the colors changing with driving profile.
Some of these may be possible with the decoder, if it can "sniff" those commands. But earlier BCM's may not have the settings for these things anyway so there would be nothing for the decoder to "sniff," if that makes sense.
Yes, keys have to be adapted... but that's a 3 minute process/ It can be done separately (if you were to replace a key, for example) but I don't consider key adaptation as a secondary step. Adapting keys is part of the BCM guided replacement function. If you're taking care of component protection you're already connected, what's another 3 minutes, haha. My car does not have KESSY, you still need to adapt keys for immo and so the remote lock/unlock will work.
.397618/
