I received my quad of TCP115-4 woofers yesterday. I broke them in for an hour, let them sit while we had dinner, then measured them with my WT3. These drivers look like they use a very similar stamp steel frame and magnet as the Designer Series, with a different cone, dust cap, and surround. The good news, 2 of the woofers measured nearly identical to each other and very close to the factory specs. The bad news is the other two measured very differently. One of the bad ones has what looks like large areas of glue soaked into the spider. It has an Fs of 69.29 Hz vs. the factory spec of 53.8. Qts and Vas are both about 30% off.
I called PE and they are sending me 2 more for free. I hope the new ones measure like the two good ones.