I agree with Richard. I never had Dynamic Routing on my Mk4 Nav, but had the BM54 swapped out under warranty and the oprion appeared under the route type selection menu (where you can select shortest, fastest, motorway etc).

This definitely was not a coding requirement for the BM54 as when I queried the dealer & the Tech about how this option works, they didn't have a clue what I was on about - so it is definitely an option that magically appears in the menu when the later BM54 is installed.

Was this the Lithuanian seller that seems to have tons of modern BMW spares? I was tempted at one point to get the very latest CD Changer from him so I could read MP3's ... was just too suspicious of where he gets the stuff from (stolen and stripped high-end cars per chance?)

As for the date from when this mod was incorporated, yes I think it was the latter part of 2005. I believe my BM54 was manufactured in April 2006. The ebay text is a bit misleading but he could claim that the 'dynamic' bit of the routing he refers to is that with TMC it will inform you of delays. He didn't misrepresent the manufacturing date, so you may have difficulty in making a claim.

Did you pay by PayPal? Does his ID have PayPal buyer protection? If so, you may be able to make a claim via PayPal as 'Item not as described' and state that Dynamic Routing is a very specific BMW term that refers to the ability of the Nav to AUTOMATICALLY reroute around delays without manual intervention.