Thanks guys. Erik, the PST-8D does have LiFT, and I have noticed a difference since I added it a while ago. It’s definitely quieter, but perhaps also softer, more rounded. As some folks have said that while they notice a difference, it doesn’t always mean it’s an improvement.
I should add that my room acoustics are sorted, and I'm very much happy with the way things are sounding. I’ve added some acoustic panels and stabilized my equipment, added plants and that sort of thing. I’m pretty much at the end of my rope of diminishing returns -- not willing to spend thousands more on the system, but just looking for the final touches.