Hello , newbie here. I love this car , but when slowing down to a stop , or accelerating , there is a noticable clunk. Also making a tight turn seem to get some resistance from the drivetrain. Basically it groans a bit. Any ideas so I can tell the dealer what it may be?. Thanks in advance.

Perhaps you have 2 different problems. Best bet is to take the SA or forman on a drive and show him whats going on. Could be one or two of several things causing this.

How can you tell the resistance from the drivetrain? E-Class has a very tight steering radius. Are you making the tight turn too fast? Ask them to check the front wheel bearings. Well know issues on these cars. Easy to check if the car is on the lift.