from what i have heard, as posted on page 1, you will not be able to fully disable the
A4WD on these transfer cases unless you put in a new switch and ecu to put it into 2wd. and im not even sure if you can do that with ours, you might have to replace the whole transfer case.
slo, as for you, you would defintely have problems running 2 different size tires if you had a blow out. if i were you, get a tire that is equally as tall (doesnt have to be as wide) that you can run as a spare. you can get them from a used tire shop pretty cheap. can even mount it on the stock spare rim.