I would go 3PI because as good as the JBL woofers are, they need some power to "come alive" and that means higher volume settings. The 3PI gives up a bit of sensitivity to play at lower frequency.
Wayne just changed the upgrade path so only he has experience there. I built a basic stock pair and they are very nice. Another possibility is 2Pi towers. You will get good efficiency, an easy load for a SET amp, and bass response that doesn't require flanking subs. The tradeoff, and it does make a difference, is that it's not a controlled directivity speaker. Things like room reflections will have a greater effect that PI3 mid horns will control.
My wife usually works from home telecommuting and uses the 3PI's for low volume background jazz listening. I hope this info helps.