How many miles are you getting out of the 18" All Season tires?

what do you mean?

I think it is well to early as the car is new. When I checked thread wear a few weeks ago I estimated I would get 40,000. I would be very happy if indeed I was able to get such milage out of these tires.

I agree with MoFex on the 40,000 projection. The Michelins should hold up better than the Goodyear RS-A's on the first generation CTS (20-25K on the all seasons).

it's too early to make a judgment now

I current have a 2006 CTS that I got only 21,000 on OEM tires. My lease ends Sept and I plan to get 2009. Since I lease them on a 36 month 10 mile per year lease, if I can 30,000 I will be fine.

Anyone have any idea why the Goodyear OEM tires on the first generation only got 20,000 - 22,000 miles? Do you think it was done to get low ball price from Goodyear?

Probably that was a aprt of it.
It woyld be if I owned Cadillac.
After all they are building to a price point.

But having said that, HOW you drive, WHERE you drive, and how often you check inflation and rotte tires have a lot to do with it.
on my 2003 Murano, we ran 235/65/18 Goodyear Eagle LS.
Some people ran neary all their miles in town, rarely if ever ratated, drove with Jqckrabbit starts and hard braking........and got in the mid 20s.
I drove some town, some Highway, rotated every 5000, medium starts and almost always easy braking and bot new tires at 36,000 , and the tires had a good 5K left in them.
We hd a few folks who did almost all Highway that got 50-60 and even 70K miles out of the same tires!

I haven't seen enough of these tires to hazard a guess as to my tire mileage.

Back to my 04, FE1 suspension. I rotated my RS-A's, watched tire inflation carefully and drove a lot of highway miles. I believe the RS-A's had a very soft rubber compound that made them stick to the road on dry surfaces and wear quickly but were not good on wet. I used snow tires in the winter as I got ZERO traction on snow. The Michelins on the 08 were OK in light snow but useless in deeper snow (6"+). Hope this helps.

Back to my 04, FE1 suspension. I rotated my RS-A's, watched tire inflation carefully and drove a lot of highway miles. I believe the RS-A's had a very soft rubber compound that made them stick to the road on dry surfaces and wear quickly but were not good on wet. I used snow tires in the winter as I got ZERO traction on snow. The Michelins on the 08 were OK in light snow but useless in deeper snow (6"+). Hope this helps.

Yes it does help. I did all the same on my 2006 got same results. The slick on wet roads in one reason I am considering AWD on 2009.