devinplombier
Think of it like the CS 7 to CS 7.2 conversion. Same cabinet but drivers upgraded and vital cover parts. In the CS5i the bass drivers were upgraded.
The CS5i is the way to go. With the right amps and room it would take a considerable amount os scratch to better them. After the future upgrades that will be offered that will be even harder to accomplish.
They go lower than any sealed cabinet speaker on the market still I believe. I have two pair in walnut and rosewood and they hit like a hammer in the bass.
This is my personal favorite Thiel speaker. I'm tweaking the room for them to perform at an even higher level.
Again monster amps to clear the throat from these beasts. The front baffle is incredible. Never have I seen one like this before.