Rel is generally considered to be better subs for 2 channel with its ability to blend seamless and dissapear. Velodyne makes excellent subs and the digital correction is a great feature but sub for sub I would go for Rel. I have heard a moderately priced and sized B series (forgot wich one) that was amazing. I ended up buying a Martin Logan Descent and will probably add an sms-1 someday.
