Sub for Totem model 1

If you can't afford the Lightning, why not try the Toten Dreamcatcher sub? Especially if you have a small space.

A second vote for the Lightning, even though it's beyond the stated $500. Cheaper subs may be great for HT but to pair with a speaker as good as the Model 1 you'll be severely let down with something in the $500 range. It will be really tough to integrate a lower-end sub and still sound cohesive musically.

You want fast musical sub, and that is a challenge for less than $500. What comes to mind is Pinnacle Subsonic (two 6.5" drivers & 350 watts), available for maybe a little more. Another option would be HSU VTF-Mk2, whick sells for about $500 (one 10" driver and 350 watts). While not matching the performance of a REL, these should blend pretty well with the right placement and provide you with good results. Good luck!

I would highly recommend the Totem Lightning sub. I friend of mine has this sub in conjunction with the Totem Tabu speakers. Fantastic sounding combo. Used price is around $800-900. I wouldn't go with anything less for your Model 1 speakers. Save up if you need to.