Curious what other people have in their systems that’s a total sleeper. Mine would have to be a pair of Pioneer S-Z9. They were released circa 2008 bundled with a pioneer network integrated amp. Original MSRP was $1800 USD for the system. I ended up buying these off Canuck audio Mart new old stock (sealed in the original boxes) for $200 Canadian shipped.
They actually were a collaboration with kef, with the drivers originally starting off as 7th Gen UniQ drivers but use TAD (also owned by pioneer) carbon/Plastic/ injection molded matrix cones (3 layer) to improve cone stiffness and dampening, Instead of the molded ridges kef uses on there poly drivers. They are pioneer cast aluminum baskets as well. Crossover also appears to use high quality brands on the caps.
They are very well built, piano gloss finish, 21 pounds, and have a frequency response of 36hz-50khz!! Seriously I have never heard bookshelf speakers this size that go so low!
They are 4ohm and only rated for 50 watts RMS but I’ve been using them at my computer with a bel canto s300i (300 watts RMS into 4ohms) and they sing!
My receiver, a Heathkit AR-1500a. An early/mid-70s granny radio-looking thing; it clocks in at ~60lbs and tosses out 60wpc @ 8 ohms and 100wpc @ 4 based on the conservative ratings of the day. It has power for days and drives my Thiels with ease. I’d put it toe to toe with any comparably powered amp of the era.
I built the integrated amp 35W/Chan version in 1970. Had a pretty noisy phono preamp, but sounded very good with my Large Advents playing Hendrix, Tull, etc. I got a used Quad 33/303 to replace it eventually.