Being an owner of an e46 318, I thought id give you an update on some prices from the dealer in preston. My engine dipstick had croded, so needed a new one. Phoned BMW Bowker Preston and they quoted me £9.50. Picked it up the next day. I thought this was a really good price considering
a. would defo have been more expensive from ebay for a second hand one
b. contacted 247spares.co.uk and they quoted me, wait for it, 20 pounds plus 12 pounds delivery for a second hand used one. This would have cost me £32. Unbelievable.
BMW Bowker quoted me £34 for a set of new shape windscreen wipers and £24 for a passenger side primered mirror cover.
I think moral of the story, check dealer first, especially in the case of the dipstick.