2001 S4 nearing 50k miles...

Hello all.

Been lurking for a bit, after having recently bought a 2001 S4 with
about 45k miles on it. First of all...what a fabulous car. I believe
I will definitely enjoy this beast.

Anyway, three primary questions...

First is what are the major maintenance/wear/service items I should
pay very close attention to as I get closer to the 50k warranty mark.
I want to get the dealer to cover as much as possible, so if I know
what to look for or have them look for that wouldn't hurt.

Second question is what the consensus is regarding extended warranties
on this car. I'm generally not a big believer in extended warranties,
as if they made sense for the car owner on average the companies that
offer them wouldn't...so obviously they make money. The question is
whether this particular year/model is one that tends to be on the good
side or bad side of that curve.

Third, I know there are a lot of different chip manufacturers, and I'm
wondering also what the word is on whether some warrant more attention
than others. Are there any that have a bad reputation? Basically, if
you have one, let me know how you like it and whether you'd buy the
same one again.

That's it for now. I know these issues have probably been hashed out
before, and in running searches I find bits and pieces, but I thought
I'd try to boil it down to a few questions.

Thanks in advance

BDWood
01 S4