Thanks that's a very useful link. They look like they should fit but front wheels would have a 4.24% speedo error, will need to do some more looking through old posts for advice on that.
Checking out some winter wheels, these look like they would fit an E86, correct? They are from an E89 size 17" x 8 with 225/45 tyres.
http://www.bmwstylewheels.com/bmw/276