Here are some Solex locks that are more pick-proof than your standard Datsun locks. Rusch Motorsports in Sandy, Oregon installed them on my 510 (two doors and the trunk) for $175. I am very happy with the upgrade! 

If your just interested in the lock they can be purchased for $125.

These locks are practically impossible to find in the US so if you want them ASAP get them from these guys! 

For more information contact ruschmotorsports@hotmail.com