I thought Mercedes required a special tool to spread the front wheels to do a proper alignment.

I've owned MB for nearly 20 years. On our first one, it was delivered with the wheels out of alignment. I took it to a private alignment shop recommended by the dealer (MB guy was on vacation). That alignment didn't last. Had it done again at a MB dealer and it's lasted for 17 years. My '91 300E has been perfect since I bought it new.