Would Martin Logan Spires benefit from subwoofer?

I would normally say ML Descent because it is easily setup to go with your MLs most likely...But JL Audio is one serious sub.

In the end, with your room, if you can do 2 subs, many people say [properly set up] it is far smoother. And i can imagine that is absolutely right. So i would say 2 ML Depths.

I just bought a JL Audio F113 sub to go with my Martin Logan Spires. Should I still use the powered woofers in my MLs, or should I just unplug them and let the JL do all the 80hz and below work? Or, any other ideas???

Is this for HT or a 2 channel setup.

This is exclusively for two channel stereo listening.

Run the MLs full range including their powered woofers and blend in the JL below that. The Spires provide an extra advantage for integration with the sub thanks to the Spires' +/- 10dB woofer adjustment centered at 35 Hz.