My experience with super tweeters* is that they give off a greater sense of ease and refinement more than anything else but also in a weird psycho-acoustical way improve perceived bass response. I really can't recall if intelligability improved so I figure that it wasn't dramatic.
VR4 Gen2s were the very first VRs I heard. Having been discontinued, I ordered Gen III HSEs instead shortly after. The Gen IIIs were more veiled than the SR Mk1 and the SR Mk2 brought even greater transparency. If midrange definition is what you're after what I can guarantee is a factory upgrade of the drivers and crossover. I know a Gen III can be fitted with SR technology but I can't be sure of the Gen2 since I never lived with one. You'd have to check with VSA on that.
Best of Luck and Happy Hunting!
*Experiments used the Townshend Maximum Super Tweeter and not VSA supertweeters although my VR-9s come standard with the latter. Speakers experimented with were VR-2s, LSA2 Standard Towers, Keith's DB-99 SEs, VR-5 SEs, Harbeth Compact 7ES', Quad ESL 57s and Quad ESL 2905s. Results were consistent with all the speakers except the VR-5s. The VR-5s had no performance gains with the Townshend in fact it was the opposite. The Townshends didn't contribute anything and when it finally did by bumping up their level controls, the sound became hard and fatiguing.
