Mike Jackson. If you want better than LSI’s, find a pair of MWM’s. They are better. Just much bigger. 

Very cool that you are at least considering keeping them Klipsch LaScalas have their own signature sound that I love. You either love it or hate it. Still have my pair I bought brand new in '77. As others have stated the crossovers MAY need new capacitors. There is a Klipsch authorized vendor for replacements that supposedly preserve the "Klipsch" sound. What upgrades are available? Now that there is a huge can of worms. Even the word upgrade is not allowed around here. They are modifications not upgrades. Many from here have migrated to AudioKarma. 

I'm sure by now the OP has long nodded off and tuned out of this discussion.   But back to the OP's original question of the power conditioner being worth it, I read a little about the Furman units on their website. They do not provide any technical details on what exactly their system is and does, and that in itself is telling. The most I can glean from their information is that these units provide some level of filtering and perhaps voltage regulation. They are concerned about RFI and EMI but how do they correct for it? No explanation. They offer units that do power factor correction, which is a power delivery efficiency issue, not an audio quality issue (fewer amps are needed to drive the load with power factor correction).   I could get into another long technical discussion, but I'll try to avoid it. In a few words this sort of "power conditioning" is not worth the price tag and will not correct many of the real-world problems present in home power systems. Period.   If you want RFI and EMI protection, install twisted pair power wires in metal clad shielding or conduit is the accepted method. And keep the wires away from motors, transformers, and strong magnets.   The filtering is almost certainly filters for high frequency sources (such as digital sources), but ignores the most common noise on power lines which are 60 Hz and lower. These are corrected with isolation and shielding. And you also must not connect digital sources (your CD, DVD, streamer players etc.) on the load side of the power conditioner.   As I discussed previously, if you need voltage regulation, you got bigger problems than your audio system. Do you share power with an industrial plant?   Another high dollar, snake oil product IMHO. There are more cost and performance effective solutions.

I mainly eat salmon and not much of other types of fish. That was the last one too

"Must be zero" but it will never be...this is common misconception. Neutral is bonded to ground at service entrance. And if no current is flowing in ground then at that point it is at the same potential. Now 50 feet down a piece of 14ga romex wire that has 15 amps flowing through it... no way is it at the same potential.

im ready to pay extra :) Im definetaly need more tweeters. But how?

Please look. 2 piece R41 + subwoofer

Got it thanks. If I would order that through Amazon, Im sure it would ship from Italy...

As I wrote the potential (voltage)between the ground and neutral must be zero or a current will flow somewhere in the system. For there to be a voltage difference between the two, equipment connected to the conductors also are connected in some way to another ground, and the two grounds are not connected directly together (there is a resistance between the two ground points). This sets up the ground loop. I'll say that we are saying the same thing.     If wired correctly, if there is a fault on the load side of an iso transformer, it clears back to iso transformer through the ground wire.  The iso is the new separately derived power source and is not the house or utility power source. It is now its own system with its own ground. All grounds need to connect back to the power source - the iso. Connecting the secondary side ground to the primary side ground not only defeats the purpose of the iso transformer, but you are potentially setting up a dangerous condition.   Think of the iso transformer as the utility and everything connected on the load side would be analogous to your house electrical system. And as such you need load side circuit breakers to protect wire and equipment against overloads and short circuits. If you are concerned about personnel safety or arcing fires you can also install GFIC's and AFCI's on the load side. But I would be judicious about using these as you could be susceptible to nuisance trips, a real PITA.

Not a Klipsch design.