vc213 - every car ive been in has made some form of whine when the a/c compressor is engaged and i dont think a sv6 is any worse than any other car (tho i havent heard your particular car, mine whines but u cant hear it over intake and exhaust noise anymore)
personally i wouldnt be paying more than 26k for an 05 sv6
thats what i paid 6 months ago for a car with 15k with leather interior and brand new rubber (was on the lot with a set of 19's and they were asking an extra 3k for the 19's-keep dreaming. asked for the std wheels and got a set of the std 17's with spankers potenza's)
the only thing that sounds iffy on them imho is racket they make when u start em up (heat shield tapping is preety annoying)
look for the 'upgraded' 05 model which came with std side airbags and lsd diff