As I was researching the set of tires I bought for my 2004
Subaru Impreza WRX. There were Pirelli P Zero Nero M+S in
P205/55-ZR16 size, made in Germany with a marking of 02/04.

My tires were marked with a UTQG traction rating of A. I
noticed that the sidewall picture in the dealer pamhplet showed
a rating of AA. TireRack (where I didn't get my tires) indicates
that most of the sizes of this model come in both AA and A
traction rated versions, including my size.

I recall someone ("J.") posted in r.a.m.h last year that the
difference in the AA were in where they were made.

--quote--

"Be aware that U.S. Pirelli cannot explain whether this tire
has the advertised UTOG traction rating of 'AA' or just 'A'.
Tirerack, NHTSA and U.S. Pirelli claim the superior AA rating,
but the sidewalls of all four tires say A. Pirelli says this
tire used to be made in the US and the new compound did test
at AA. However, production was shipped to Germany (my tires
are dated 4th week of 2004 and marked 'Germany') and U.S.
Pirelli is still trying to get an answer from the factory as
to what compound and what rating the tires really have."

--end of quote--

I sent a message to Pirelli's US division, and got a rather
useless answer that "AA provides better traction than A". I
wasn't satisfied, and called their 800 number -(800) PIRELLI.
When I asked the question, the operator put me on hold, went
for someone more knowledgeable, and answered back that the
rubber compound used in the German tires is different, but
shouldn't result in poorer performance.

It might simply have been a snafu in how they marked the tires
or the sequence of tests run. I'm guessing that they probably
would test out to the AA traction rating standard. If they're
working well, I'm not going to worry too much about whether they
have an extra A.

Regardless, the tires seem to work pretty well compared to the
Bridgestone Potenza RE92 tires that came stock. They seem to
corner much better in the dry and wet, although they are a bit
squishy. I haven't checked out their hydroplane resistance
(only light rain so far) yet, but the huge water channels look
like they should help. They're a bit noisy now, but I've got
less than 200 miles on them; they might quiet down as they
wear in (or not).