Billy

Without having your chasis no to hand Realoem suggests that the part number is 13621432356
http://realoem.com/bmw/showparts.do?model=DT42&mospid=47541&btnr=13_0919& hg=13&fg=15

If you cross reference 13621432356 on Partsdb.info http://partsdb.info/autopart/bmw/13621432356
you can see the list of manufacturers for that part

If you then take that part number - in this case I'll take VDO (5WK96050Z) as Bosch is not listed - you can search, amazon, ebay, gsf, ottoonline, mister-auto, maf-shop, micksgarage etc and get the cheapest

http://www.amazon.co.uk/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=vdo+5WK96050Z

http://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.T RC0.H0.Xvdo+5WK96050Z.TRS0&_nkw=vdo+5WK96050Z&_sac at=0

http://www.maf-shop.com/product_info.php/info/p44_59605.html

http://www.mister-auto.ie/en/search_s_refoem_13621432356.html

http://www.ottocarparts.com/shop/search?orderby=position&orderway=desc&search_query =13621432356&submit_search=Find+part

http://www.gsfcarparts.ie/catalogsearch/result/?q=13621432356

http://www.micksgarage.com/search.aspx?fffBrand=STANDARD~~~Quinton%20Hazell~~ ~Meat%20%26%20Doria~~~HELLA~~~ERA&fffDepartment=Ai r%2BFlow%2BMeters&fffMake=bmw&fffBasemodel=bmw%205-series&fffModelDescription=5%201995%20to%202003&ff ftd_car=525%20i&fffBHP=192