I did the replacement this morning. Took me 20 minutes. I decided to go with the NAPA Legend 75. Its rated at 900 cca and it fits perfectly exactly like OE. I got an additional 7% discount because of CAA membership, so the final cost was C$ 198.92. I just can't justify spending C$267 for the OE. There is only one MB dealer in this province so they really got you if you need OE parts. I remember having to replace a cracked side mirror housing. And it is just the outside housing without the mirror, motor etc. and it was $150.

MB roadside assistance is only good in Canada for the duration of warranty period, so I was way past that. My CAA membership do provide battery service and they will also replace your dead battery on the spot with no service charge. They also comes with a 3 yr free replacement with additional 3 yr pro-rated afterwards. Unfortunately they don't carry the size for the ML. So I was out of luck.