How do you know if this vehicle is an OHV or the SHOC?

What is your question?

I am trying to replace the plugs and wires ordering off eBay and it asks for the trim hence OHV or SHOC. And I can't find anywhere where I shows it. I would appreciate help ASAP. Thank you in advance.

What makes this problem better or worse?

Nothing makes it better and it can't get worse

How long has your 1999 Mercedes-Benz ML320 had this problem?

2 years