newbie questions ... (snow tires, and octane number)

[achopde@avid.com]

So, I just got myself a used Audi 100 (non-turbo), and going by the
current discussion in this list, it is imperative to move over to snow
tires in winter (MA/NH driving).
How important is it to change the tires? Does everyone change over to
winter tires, or is it ok to keep the fat tires, and just drive *very*
carefully? 

My second question is about octane numbers. The car manual suggests that
one should use 92 octane in the car. Now, I have always assumed that the
reason car manufacturers insisted on higher octane gas was because of the
"detergent" additives that were missing for lower octane gas (some years
ago). So, what is the general opinion out there? For regular driving, do
you really need high octane gas, or will 89 or 87 octane gas do?

Thanks for any opinions....
----
Avinash Chopde       (508) 640 3138
avinash@avid.com     Avid Technology, Inc.     Tewksbury, Massachusetts, USA.