2004 Volvo S60

I wanna buy a 2nd hand 2004 Volvo S60. I have the following questions:-

1/ Is the maintenance fee high?
2/ I am worried about the minor problems such as air-con or hi-fi system.. what are the most frequent defects that you see on a volvo car?
3/ as far as I know volvo does not use V5 so is the noise of engine loud when you drive?
4/ How are the 2nd hand market go for Volvo?? Does it depreciate a lot every year?

Thanks.