Expensive tweaks-are they worth it?

Specifically Walker Audio (High Definition Links) $300/pair and Argent Audio (Room Lenses) $400 each (3 recommended) Thank you . Yoby
I found that the Argent Room Lenses were one of the most cost-effective and significant tweaks I have ever used. Bass performance in my room was much improved with deeper extension as well as taming a mid-bass hump. In addition, soundstaging was dramatically improved with much better delineation of individual instruments and vocalists.
I agree with Albertporter, the Walker HDLs were a definite improvement to my Maggies. I use 2 sets because they are biwired. I purchased them after hearing them on a pair of Sound Lab Ultimates. He correctly points out that your system must be 'mostly correct' to appreciate them.
The Walker HDL's do make a difference. Whether that difference is a good thing or a bad thing is purely subjective. Thing is, $300 will buy you a fat stack of records. Something to think about...
The Walkers do make a difference on my dynamic system as well, although I think they're expensive for what they are (not the improvements). The designer of my speakers did a measurement at the tweeter with the HDLs in and out of the system and there actually was a measurable smoothing of the treble output. The room lenses didn't work for me, but my system is almost an omnidirectional one, that probably has a lot to do with it; on a more conventional speaker system my result may well have been different.