What do I need to fit a RNS E Media System into my A4 B7?

I know there's loads of posts on here about this but Im a total newbie so need it explaining in more simple terms.

OK so I currently have a concert CD player with a bose system and I would like to have a RNS E media system if possible?

I need to know a few things:-

1. What would the best RNS e to buy?
2. Will it effect my bose system?
3. Is there anyone in the Teesside area that fits these?
4. How much will it roughly cost to get fitted?

Thanks guys.
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Nice one, cheers Gary.