Rel subs with Magnepan 3.6's

What Rel subs (I plan on buying 2) on a budget work well for 2 channel using Magnepan 3.6's? My room is roughly 14x35 with my system on the long wall. The ONLY other sub I am considering is SVS SB2000. However strongly leaning towards Rel as they hook up to the amps, so better synergy. Thanks for any input!