The plan is this:
Have new tires put on Saturday, bring car home, do some measurements at home (esp camber), and see if things look bad. If so, buy the K-mac, put it on myself, then take to the dealer for a laser align.
OK, shoot holes in my plan....
lol....your money, but tires aren't cheap - for good ones at least.
Do you have proper equipment to measure camber, etc. on the car? Who knows....you may live a great distance from a dealer and therefore don't want to risk driving on corded tires?? If it's just on one side, throw on the spare....
If your alignment is out of spec, your new tires will begin to wear immediately. Depending on how much out of spec, they can be corded in as little as a couple thousand miles. Since we cannot rotate this pricey ruber, it's important - at least to me - to have a thorough job done right from the beginning. FWIW, I have always done an alignment and high-speed balance (I use Butler here locally) when installing fresh rubber.
Hint: You can purchase tires at the MB dealership, have them installed, balanced and aligned all at the same time. Several of the MB dealerships here in ATL will even price match with others on the tire pricing, so unless you're getting a bargain basement price on the tires, I don't see any advantage to taking the car several different places.
Hint #2: Assuming you can purchase tires super-cheap, you can even bring your own tires to the dealership and have them install, balance and align to spec.
IMO, you don't need K-mac parts unless you put on larger wheels and tires, or have the suspension lowered.