[s-cars] Battery question

[Lee Levitt]

I spent some time on the Optima site and have a couple of questions:

1 - they don't list an application for Audi. Is this because their battery
does not have an external breather tube? Do you need one with this battery?
(Of course the battery selector doesn't seem to work for *any* car I
tried...)

2 - red versus yellow top - which is recommended and why? Any reason not to
go with the yellow top?

3 - Are there different sizes of Optima? What model are people buying?

4 - Any installation gotchas?

Thanks!

Lee
'95.5 S6 avant (Bilstein/Eibach/Euros/HID/BIRA S3)
'96 A6 quattro avant (Euros)