Conditioner vs. Surge protector

My 2 cents:

Buy and install a whole house surge protector first.

You can always add more protection down the line. 

This way all your electronics have a minimum of protection, not just your stereo.

B

Please be aware that as of 2020, the NEC requires a whole house surge protector.  They are relatively inexpensive and effective.

Here's a wholesale link to FS140 if you are going to have it professionally installed.

Not familiar with the company, but it was in the first 5 hits I got with a WWW search.

I live in the Los Angeles area and surge protect everything that needs it.

I second Mapman's recommendation for Siemens BoltShield.  I installed two of them since I had two free spaces on each side of Siemens Panel.  Total of 60kA x 2 = 120kA.  In addition I plan to add Siemens QSA2020SPD. (about $80) replacing two circuit breakers with one leading to audio system.  The reason for it is that protection element is always protected by circuit breaker.  When circuit breaker switches off during high voltage spike protection element won't protect anymore, but since audio system is connected thru the breaker it will be also discontinued.  It is only 10kA, but it adds important protection for audio system alone.

Please take a look at this App. Note on MOV surge protectors:   www.onfilter.com/protection-from-transients   
In short, MOVs do pretty well once their breakdown limit is reached (~400V and up for 120VAC systems, ~600...900V for 250VAC); they don't do much at all when the surge peaks are under that voltage.  A spike of 300V can get through to your equipment unimpeded if all you rely is MOVs  Also, watch for MOV's "expiration date" of a sorts - with every absorbed spike they wear out a bit until becoming essentially non-functional.