Qualitatively, my three REL subs have failed after a few years of ownership, so quality is no longer an attribute associated with price. I bought an R then a T and then an S version and they all had failing parts. Quality engineering at REL may not exist in their design or manufacturing.
Just get the T/9x and use the remaining funds for other components or music purchases. No one at my house has noticed a difference between the T, R, or S performance.