Buck 5,000+ posts
little alien on campus
Originals used a chunky 3.5" coil. Prototype in the teaser video from Kicker had 3" 4 layer coil and a very tight gap. The old ones could definitely take some power though, the new ones not so much but I expect them to be very efficient.
It's been so long I've forgotten. It'll be cool to design for a new one, hopefully. They're still square?