INdy says to replace O rings on box under intake?.
 

as well as the o rings on the fuel lines to stop poor running/air in fuel lines? This is on my w210. I hope he doesn't mean delivery valve seals because they were not leaking. What is this box under the manifold he is referring to? Help me out here I don't want my wallet going for a ride:eek:

IMO it's not a bad idea to replace every O ring and fuek line while you or he is doing the work, including the delivery valves. Do a search and you will find a ton of info about fuel leaks on these engines, a bit of a PIA, but a relatively easy fix and really cheap if you DIY, a bit more if you hire it out.

A "box" beneath the IM would be the IP (dv's), the shutoff valve or lift pump connected to it.

If doing the DV's, make CERTAIN the mech is expirienced as is easy to screw that job up and cause damage to the pump. IMO if the mech can't give you the proper name of the components beneath the IM i'd be leary of them doing that job.

Like Len said, if the IM is comming off, go ahead and repalce every fuel line (or o-ring) at that time and clean the gunk out of the IM also.