Is a high priced Line Conditioner needed

I just bought a used Furman Elite-15DMi, plugged my mono blocks into it and it took away the 60 cycle hum I had, plus music sounds better, as claimed. I didn't believe it would improve the musicality of the system, but it did!

Can anyone using a Furman Elite 15i tell me whether it will boost voltage during "line sags" ? I understand it protects against surges. I've visited the Furman site. I didn't read anything claiming voltage boost for this unit so think it does NOT. Am looking for confirmation one way or the other. Thanks in advance.

In my opinion, one has to try and experiment with power conditioners to determine which is best suited for their system, their tastes and which components to use conditioning on.
With that said I agree with the comment Nonoise made on 09-21-13: regarding the Blue Circle PLC 2X Thingee. Or you might want to try the new and improved PLC (Powerline conditioner) Thingee FX2 X0e, in a 4 or 6 outlet availability. I have experimented with these units and there is a lot of bang for the buck without spending huge dollars.
If you do want to spend big bucks, take a look at the Bybee, Equi=Tech balanced power or the Dmitri conditioners.

The Furman Elite 15DMi doesn't change the voltage. It linearly filters and monitors voltage.It will shut the outlets down if voltage exceeds 140V or 85V.

Thanks for that input, A$280.