Welcome to the forum @dogman. I'm late to the party but best of luck with your T3+. One thing I don't believe has been answered in reference to your question is no, the load on your system's power amp is not reduced because it does not have to drive the woofer. The speakers impedance is what it is. However, that said, invariably you should find that your amp doesn't have to "work as hard" to produce the same decibel level it otherwise would if you didn't have a powered sub in the T3+.

Hi, Dogman

This is probably overkill at this point, lots of good answers..

Since the powered amp in any of the powered Tritons takes over the bass heavy lifting load, I think it’s safe to say the load on your source amp is less because of the Triton amp’s help.

So, in answer to your question re the relative power draw needs from an external amp of your T3+’s vs T5’s, my take is that any powered Triton needs less power help from an external amp than any 100% passive speaker, including a T5. Moderator Dude can correct if that is incorrect.

Enjoy your T3’s! You have chosen well!

Rick