LOL, mine was fine too. Just needed a quick boost from my basement-stored (with Battery Tender Junior) Costco marine battery and then a couple of battery charger sessions to get it back to normal. Everything looks good with the Princess Auto Autel AL439 tester. I think the car didn't see enough use as we entered the cold. Started up just fine both yesterday and today which were even colder mornings, around -15C or so.
But that first day I did lots of preliminary shopping and thought I would post up the results. First of all, when this 6yr&1mo old battery craps out, I will be getting another OEM one from the dealer.
The old Varta part # 5K0915105D has been superceded by a stronger one with part # 000915105DEDSP. The old one has served me well and the specs are changed (i.e. improved) as follows: 60 Ah to 61 Ah, 280 A DIN to 330 A DIN, and CCA of 480 A to 540 A. Two dealers at $138 and one at $139.38. Since my weaker one is past six years and still going, the new one is what I will eventually buy and stay OEM and hope for even lengthier and superior service.
Costco had two listings for the '12 GTI;
# 270552 Kirkland Fitment Code 24, H6, 730 CCA, $119.99
# 1114556 Kirkland Fitment Code 32, H5, 650 CCA, $114.99
Walmart had two as well, only one in stock to look at;
Maxx EverStart MAXX-47N, H5, 650 CCA, $136.97
Maxx EverStart MAXX-H6, H6, ??? CCA, $144.97
Canadian Tire seemed to have six choices ranging from $133.99 to $209.99 at the time.
A parts place on Elgin Mills offered two;
Exide (Classic?), 600 CCA, $161.59
Dealer OEM again for me, when the time comes! $138 seems OK.
You sure that replacement battery from the dealer is another Varta?
I could be wrong, but thought I read that the replacement batteries stocked by dealers are made in North America, and not the same Vartas that came as OE in the car from Germany.