Door is very hard to open from the outside

It takes a fair amount of effort to open my drivers side door recently. I have read that a little lube might fix the problem but I can't imagine that it what is happening here.

I have a 2003 M3 convertable.

Thanks in advance for anyone's help.

When you open the door, and look at the latch, you will see a little rubber plug about 3-4mm in diameter.

1) Pull out the plug.
2) Open the trunk toolkit and take out the z-shaped allen key.
3) Insert the allen key into the hole.
4) Turn the screw to the position that tightens the screw until it is very snug. (It may be reverse threaded, I'm not sure.)

This should make it somewhat easier to open. I did this to my passenger side door and it worked, not sure if the screw threads are reversed for the driver's side.

Hope this helps.