I can't remember how much it cost me. It's been almost 2 years now.
If you've got a GT TDi, then I'm happy to share my tune and tuning software for you to flash (MPPS)
I've got an 06 2.0 TDI, but it's not a GT
Also, I was under the impression you can't share tunes? Or are you talking about something different? Is an ECU Flash Tune different from the type of tune people talk about when referring to APR, Revo etc?
Unfortunately, my tune won't work in your car. They're vastly different.
Mine was a download of the base map, and tweaked to produce more power. It's unencrypted and a bin file, so I'm sure it'll work on other GT TDi's
I don't know about Revo and APR but going back to my Subaru days, I know MRT ecutek use to encrypt their tunes, to prevent people from copying their tunes. I would imagine they'd be similar to protect their intellectual property.