bro Game - R,
E46 doesn't have a small "skis" access port between the booth and rear seat arm rest, does it? - Nope it does not have the skis access. I've checked on it earlier.
have only one keyhole (other than the boot) on the driver's side door right? - Yes
Have you been using this key often or most of the time you've been using the remote function only? - I Use only the remote all the time.
Try taking a long narrow metal prod or scraper and reach into the keyhole and try and scrape free any dirt or dead bugs that may have stuffed up the hole that would prevent the key from going in fully. A vacuum cleaner would help too. - They actually goes all the way in.
Then ensure that the key is pushed all the way in before trying to turn it. Every time you're unable to turn the key, pull it out slightly (0.5-1 mm) and try turning the key again. It may be possible that your key is only slightly different than your worn out keyhole and you'll need to keep trying a few times till hopefully it finally can unlock. - Have tried this, but no luck.
But from what bro tweiboon has stated, I think there were two different keys (one for the door lock and the other one for the ignition). I'm thinking of getting a lock smith to come by and just unlock the door and maybe then change the door lock.
Adviseable to do this?