I'd get 15 sq ft minimum (3ftx5ft) Better have some extra than running short, and I don't have much extra. I suggest you get a little more if it's your first time.
The crack IS visible
Have a pic of your E46 with said trim?

Little bit of a tangent...

Since its not the wood that cracks, but merely the clear ontop...has anyone stripped and re cleared them? Personally with my beige lower and black upper dash I like the look of the dark wood much more than any of the wraps I've seen thus far...

Dinoc is one of the best you can use . It very easy to wrap and cover very wells.
I had done that on mine X5 but in CF. it still on there when i sold it ,no peeling after three years.

I used 3M Scotchprint 1080 Matte Dark Grey Metallic Vinyl to cover the steering wheel trim.. VERY similar to the accents on the door handles.

Edit: Here's a link to what I used
New 3M Scotchprint 1080 Matte Dark Grey Metallic Vinyl Car Wrap 1ft x 1ft Sample | eBay


http://i1286.photobucket.com/albums/...ps6c917bf5.jpg

http://i1286.photobucket.com/albums/...psbbccff5e.jpg

<333333 Piano black

There is no metal in the vinyl. it is all vinyl. The vinyl will wrap like any other color. The color or 'look' is a computerized design printed on the vinyl.