A5 or S5?

Aside from the additional horsepower (and subsequent reduction in gas milage) are there any other distinct differences between the A5 and S5? I really love the design and fit of this car, I just can't help but think the A5 is just a bit underpowered. I don't know if the additional cost for the S5 is worth it or not, so please chime in with any thoughts.

I'm kind of looking to get a little better gas mileage than my current truck offers too, so if anyone has some real world gas mileage figures for both the A5/S5 this would be helpful. I plan to make up my mind this week and get one ordered so the wait (or LONG wait) can begin.

Only other choice I can't seem to make is manual or auto trans...this is tough :(

This forum seems awfully slow

here ya go:http://www.a5oc.com/forums/
 
there are a LOT of topics on this subject here. Honestly, from what I have been reading, there is a difference of about 5 mpg hwy between the A5 and S5.  Then about 3-4 mpg difference in city driving. I guess it depends on how aggressive you drive. I am leaning more toward S5 myself. The auto trans cars seem to do BETTER than the manual trans, but I go manual trans in cars. For a truck, esp if you are pulling something, I would get an auto :)
 
Differences between the 2 are: the sports seats, type of leather (i can't tell really from pictures), rear bumper and front bumper/grille treatment. Even the A5 S-line is different than the S5, but not by much.
 
It all depends :) Most ppl say BMW 335xi over A5, and S5 over them both. Also, insurance for the S5 is 22 bucks more a month than the A5, annual gas is about 200 bucks more for the S5 than A5. To me, I can justify the extra cost :)