Stereophile review with measurements of the little brother Polk L100 bookshelf speakers here:
Stereophile Review of Polk L100
Looks like a little bit of a tough impedance, plus a big resonance can be seen on the port output around 700Hz.
I wonder if the bump ShadyJ saw in the response of the L200 speakers around 500-600Hz is also a port resonance showing up for that speaker?
Also, the ring radiator tweeter's dispersion is quite narrow, with it dropping off to the sides (beaming) starting as low as around 5kHz.