What is under $5k speaker with best bass slam?

You might want to look at the Ariels, maybe a used 10T.

And aren't NHT speakers known for bass 'slam?'

I agree with most of these, especially the Gallo Ref 3.1 (with the bass amp), and especially the Klipsch K-horns. Those are, to me the be-all, end-all in Rock speakers. Additionally, for "slam" the Definitive Technology SC 7000 are pretty awe inspiring. One last vote, the best slam I that I have ever heard, was a buudy's Joseph Audio Monitors with a Talon sub. The sub definitely helped.

The Focus Line LS-6 from AV123 will outclass all others listed so far in terms of bass slam IMHO. Nothing that I know of can best these speakers in terms of bass slam at their price point. (They have 16 woofers total!). The MSRP of a pair of LS-6 are around $4400.

Like I said, letting those Piegas get away would be very foolish......

Shakey