I will agree with you about Fosters, heep of horrible goo in a bottle from The Fosters Group.
Try a Kilkenny or a Beck's that's all I drink now. VB was given me to many headaches but that might have been my other half also
I wouldn't worry too much about the dis-colourization, my C5 has done the same.
im not too worried about the one on the header... but the one on the muffler looks gross hehe...
Btw... Fosters = gross They dont even really sell it here in Australia.
There are plenty of other local beers which are actually drinkable