Yes they are a good idea, its hard to drain oil through a sump plug without some going where its not wanted. Those pumps don't give you a complete drain but the bit that's left behind is minimal in most cases so long as you ensure that the suction line goes to the deepest part of the sump. Make sure the oil is warm before you drain it, best time is 10 to 15 minutes after a drive longer than 15 minutes. Put a pan underneath the oil filter before you unscrew it because that always lets some oil go as well.
Sorry, I am no expert on oils and I suspect just about everyone will have a different opinion anyway but visit a mechanic who deals with European cars (not necessarily a Benz dealership) and I am sure their opinion will be more valuable than most others.
