Mike,
I wrote a long, detailed response, but my computer locked up!
Summary:
Because guides are on the bottom, they pull the rod down, no matter where the spine is. So they will never want to twist. Extremely stable.
Due to line pulling down, you only need single foot guides for surprisingly heavy rods. The one in the pic is using #8 fly guides out through the tip, yet is spooled with 40# braid. On a regular rod those guides would be TRASH.
Yet, on this rod, they make it much lighter, and yet more powerful.
Check
www.rodbuilding.org They are the experts. Do a search first, and you will find VOLUMES of information and testimonials.
Spiral rods are good stuff. I'm 100% convinced, and will not be going back.
Good luck!
TH