Need help ASAP with AKG 270. How much should I pay?

[Feanor IV]

Hey there,

I was thinking about getting a set of AKG 270. So, here's a couple of questions:

1. How do they compare with my AKG 171? Should I buy the 270?
2. Is there a significant difference between 270 Studio and 270 playback?
3. How much would you pay for a used pair of each of the two?

Please help me out because I need to buy them before the Tuesday, if I finally want to

Thanks,
Menelaos