I agree bhatt...and if the keyless part stops working, the 'old-fashioned' key in the lock still works.
I bought a similar system and installed it without problem.
You might also check out 2phast's website, he installed a similar system on his 500e.
www.2phast.com/500e
This should work with any of the 201/124 cars (and others) with vacuum operated locks.