the best thing to do if you can is probably just wait until you see someone saying they will part out their car. usually at least a few times a week you can find people parting off their car b/c of a wreck or whatever at www.dsmtrader.com if you want to actually get new ones, dont go through satan (the dealership) b/c they will rape you good. also try ebay. aftermarket is usually the best way to go if you need things right away. good luck, hope this helps!
i didnt know they made fiberglass doors . you could always get some z3 fenders and fill up the holes, i'm not sure if anyone sells stock fiberlass fenders or not.
I saw at GTP Intenational they have a group buy for Carbon Fiber doors $900, but I thought they were a little expensive so I was wondering if fiberglass ones were available. Here is the link, the doors and hatchback are the last two items.