You don't need the gateway, your 2G gateway is fine.
I thought for 2g to 3g+ the gateway was required for the changes in functionality? I had the old gateway on my 2g and had to upgrade to a later model when i changed to 3g+.
My gateway was from 2011, new one was from a 2014 car.
Another question...sorry haha. Is the 3G High harness the same as the 3G+ one?
You also don't need a full replacement loom, I'll dig up my pictures of what was done one mine, basically the 2g loom had two retrofit ends fitted to it, one at the front to convert 2g cables into 3g ends for the gateway, screen and controller. the other end was to convert the radio etc into the same style of the 3g radio and amp.
Meant i didn't have to rip out the MOST cables for the car, and was significantly cheaper to do than a full wiring loom replacement (around 100GBP, if you source parts yourself)
Apparently there is a guy in Poland who can do it remotely. He has you buy a cable and plug in with a computer to some wifi. I can't for the life of me remember his name. I tried digging through the forums to find it but had no luck. Otherwise, yes the dealer is another option. I have heard from other guys that it only cost them $175 or so to do it. So I guess its hit or miss. I'll let you know once I am at that point!
Hi name is Jack Kirry - he charges 80Euro to remove CP on a 3G retrofit (that includes radio, 5F unit and for me gateway)