Is It Worth Having a Spare OVP Relay and MAS On Hand?

[regsatx]

I have a friend knows someone who just had a 91 300 SEL totaled in near Houston and he's parting out the car himself as I understand it. I asked my friend to check on the OVP and MAS and he said the guy would sell them both for $50.00. I have a 1990 300SE and the parts numbers are different because he says he's replaced both items.

My question is whether it's a good investment of a fifty just to have these on hand for my car down the road? I've read a lot about the problems they can cause.