Powerflex RTABs have a minimal increase in harshness. It would be imperceptible if you hadn't driven a car for a week- lets put it that way. I originally went with the OE/limiter setup, but for the RTABs Powerflex is a solid choice (pun intended). Everything else I stick to rubber. I'm a stickler for NVH.
"All lies and jest, still a man hears what he wants to hear and disregards the rest."