The Rhea/Phoebe require no soldering. Just pop out the CD drive, pop in the Rhea. Very simple.
The nice thing about this new solution, even ignoring that it furthers public understanding of the hardware, is that it's a simple module that plugs into a slot already available and accessible on every Saturn ever sold by SEGA (presumably it won't work on the Hi-Saturn units made by Hitachi, as they had the MPEG hardware integrated, though they are also very rare and very expensive).