Newbie ask: Euro2 and gas plant

Hello.

Soon it will be time - the acquisition of an Audi V8 is planned.

I've been reading about the gas system upstairs. Have the costs been reduced or are we still talking about 3,000 euros? Will that be cheaper if you bring a gas system from another car?

Furthermore, it makes sense to upgrade the car to Euro2. What do I have to do and what costs do I incur?

Thank you and greetings

Kai