I agree that it would be best to have a chat with Johnny R.
I've heard both, and I found the Signature more muscular and energetic than the regular, no doubt due to its increased power supply. At the same time, I found it a little less sweet or delicate than the regular, though admittedly the Sig wasn't fully broken in.
My point remains. Some manufacturers make a "signature" version of a product, but what that really means can vary considerably. Gold plated connectors, better wire, costier caps, or whatever. The Aria Signature is substantially re-engineered, though retaining some of the original DNA of the regular.