I had a pair that I used with Arcam Alpha 9 preamp and Parasound HCA-1200 amp. They weren't bad, but too laid back for me. They didn't have musicality of the Totem Rainmakers they replaced. If I remember correctly I had just over a year.
Totem speakers offer huge bang for the buck. I've owned Rainmakers in the past, and found them to be spectacular. I've heard good things about the newer offerings like the Skylight and Sky as well.
I'm not heard the Quad Z2, but I currently use a pair of Quad 12L. They have similar airiness and detail to the Totems, but lack the low end. I never used a sub with Totems, but one is necessary with the Quad 12Ls.
I'd suggest Totem speakers. I'm very familiar with the older models like the Rainmaker and Hawk. I've read great things about some of the newer models as well. There are several dealers in the L.A. area so you shouldn't have any trouble getting your ears on them.
There is a mod for the LSI15s that's documented in the link below.
https://forum.polkaudio.com/discussion/89529/db840-sub-in-lsi15s-replace-the-stock-8-driver/p1
I have a pair of Quad 12L Actives that I love. They're very detailed, but not harsh. I found the 12L2s to be brighter so I didn't upgrade. Unfortunately the amp has failed in one of the 12L. It looks like I'm going to move up to the Z1s.
No affiliation. Norman Lab Model 9 pair with the smoked glass tops. Price seems steep to me.
https://littlerock.craigslist.org/ele/d/little-rock-norman-lab-speakers/6955602019.html
Those are a very late version of the 431. Most of the run used a ribbon tweeter and foam dome midrange. Those have the tweeter and midrange of the 432 series.
The 431s were bright compared to models with the Phillips tweeter. That's why they were the only generation with that tweeter. Also, in the picture above the midrange has been replaced. The 431s used a foam dome 5" midrange. Here's a better pic
The same seller in Searcy has these for sale.
Klipsch Heresy pair:
https://littlerock.craigslist.org/ele/d/searcy-1984-klipsch-heresy-hwo-v15/6801118403.html
Norman Lab Model 9 pair:
https://littlerock.craigslist.org/ele/d/searcy-norman-lab-model-9b-pictures/6790081489.html
I've had Rainmakers in the past, and I found them to be very open. However they play much bigger than their size. I almost didn't believe that I was listening to a bookshelf speaker.