Tried these guys? http://www.bmwman.co.uk/services-ava...culate-filter/
There is also quite a lot of information on this website. http://www.sinspeed.co.uk/bmw-comple...emoval-session
If you search over on the E90 forum you'll find several members who have removed their DPFs and enjoyed the benefits.
Good luck - btw I've got no affiliation to either of the above, I was lucky enought to get my DPF changed by the dealer under AUC warranty.