I have a friend who is considering an '01 S55 AMG. It has 71k miles and looks to be cosmetically in great shape. I haven't driven it, but assuming the mechanicals are sorted correctly and it's been maintained properly, is $24,000 a reasonable price? Aside from the airmatic problems, are there other things to look for in the AMG that would put him off the car? I am generally aware of the series problems the '00-'03 W220 have, but are their peculiarities of the AMG that need to be added to the list? Thanks in advance for your advice.