4.8is exhaust tips for 3.0
 

I want the look of the 4.8is exhaust for my 3.0. Do I just get tips or do I have to get the whole exhaust pipe. Please, help. Maybe if you have a link for ecs tuning for the parts.

ECS has them. You also need a set of Y-pipes and I would recommend ordering the trim rings for the exhaust cut-outs to finish everything off nice.
Tips - 18107512709
Trim - 51127010123 (left), 51127010124 (right).

When I punched the numbers for the trim, it said heat prot. Not sure if that's what you meant I should get, don't really know what a heat prot is. Also you said that I have to get a set of y-pipes? Where do I get that and do I really need it or can I just use what I have?

Yup thats what they're called. If you look them up on realoem.com you can see what they are on the diagram.

The Y-pipes are because of the single round pipe bent down exiting the muffler. The y-pipe functions as an adapter to fit the oval opening of the 4.8 tip....

You could just use a single pipe, but looks a bit funny.

Do you have a part number for that? thanks for your help!

There is no BMW part number, it's not a BMW part. You can either get one made at a local exhaust shop or check out a local auto parts store as they usually have premade/chromed ones. Do a search for the in/out sizes, I can't recall them off hand.