To give you an idea of Current UK prices for this.
Just purchased this:_
http://www.bmw-warranty.co.uk/Pages/Home.aspx
Comprehensive, the highest level of protection.
- Term:- 1-Year deal
- Price:- £442
- Commences:- Aug 1st 2012.
It protects my now 3-yr old, 35i (currently with 12,800 miles on the clock).
I reckon it's a damned good deal
BTW, Independents wanted over £1,000