Do you have the Auto4WD system or AWD? The A4WD system has 3 buttons on the dash for selecting 4X4Auto, 4X4High, and 4X4Low. The AWD system doesn't have those buttons.

So, you now have 2 new front tires and 2 older tires on the rear? If so, my guess is that's what is causing your shuddering and jolting.

I thought that the AdvanceTrac equiped vehicles have a button on the console to turn it off. Maybe I'm confused - there is no ADVTRAC OFF?

BTW, $1200 isn't really being raped for 2 new tires, new rotors and pads at all 4 wheels, fixed your ABS problem (whatever it was), oil change, and wipers. It's more than you want to pay at Pep Boys (ok, I wouldn't let them change my oil let alone actually work on anything) but I've certainly heard of much worse.

ps: welcome to FTE!