I think if you have a new or properly rebuilt MB starter for your car, with good battery and cables and connections.... you will be in good shape...
If your car won't start with the new PGlow plugs.... and be sure to run the cleaner reamer into there when changing them out...
Then for really cold days I suggest you get the spray starter fluid out and put a 3 second burst into the air intake tube....preferably at the same time someone hits the starter button.....
This has been discussed..... lots of people who can't figure out the physics will immediately post warnings of blowing up your engine , etc...but you can do a search and find JimSmiths' definitive post... which agrees with me...