Nando,
Forget the K340.
If you want a real "bang for the buck" check out for this one:
The Samson SR850.
It's an AKG clone, but with an
EXCELLENT soundstage, and with a price of +/- $50,- new.....
Check also these parts of your AKG 240:
Those materials will desintegrade over the years, and so is the same with the earpads.
The damping material on the inside will also suffer with the same problem, but it needs some more expierence to replace it.
Note: All these problems of mileage will have their effect on the soundquality overall....
Maybe I should start a new thread for this, but I'm sure Daren won't mind to put it in here....