i might be able to help...
i picked up a 'showroom' e90 335i m sport last friday, i wanted to order my own specd car but was told i would have to wait to at least late may, so i ended up taking the 335i in the showroom (i couldn't wait that long)
i was told this is due to bmw apparently falling behind on coupe production and therefore all 335i engines going to E90 / E91's that have not already received a production slot are to be used in order to help catch up on the coupe convertible production. E90 335i's are going to be rare over the next few monthes!
I was told this by 3 dealers in kent, so i imagine theres some truth to it....
my advice... hunt for a pre-spec'd car with an definate order slot, or try and find a 'showroom' car, i manged to get a nearly list £41k car for £34k because it was a 'showroom' car. it only had 17 miles on it though!