Hi excel,
I got the prices from
www.carcostcanada.com
You pay $30 & get 5 'invoice' prices.
I priced up a 128i (see my 128i thread
http://www.1addicts.com/forums/showthread.php?t=13464) , a 135i and a Cooper S so far.
All pretty much gave a profit margin of between 6.5% & 8%
I'm not 100% sure how accurate they are but I'm sure they make a good guide.
.