Hey Belo!! Welcome to NICO!!
1) best website that I know of for parts,service and price is Everythingg35.com ask for Joe when your ready he is extremley helpful!
2) 06and 07 are very similiar, if not in a rush...I would definitley wait for the 08 for some really sweet changes!! Click on my picture in my sig. for more info.
3) Turbos go from about 5k ++ for something decent
4) I promise you this is the only forum you will ever need for any info. or advice on your car. We have over 50000 members and growing everyday. Extremely knowledgable members and staff as well as online mechanics. there is no question that can't be answered about the G here. as for local clubs...try here
zeromain?id=21
Hope this helps and enjoy your stay!! Keep us posted on your decision