In Kuwait, the choices are very limited. Apart from these two they have Definitive Technology (their plate amps infamous for all reasons of burning out), Paradigm they know how to make a decent speaker but in the subwoofer sphere their subs are average, B&W its just too costly and they have also got amp issues based on my discussions with a few technicians. Other than that they have Polk, Klipsch and KEF which I have tried but don't like them as they are very boomy and in the chest bass. Any other brands that you can recommend I can search for them or see if I can get them shipped from around the GCC region.
What SVS models does your dealer carry?
DefTec also have exaggerated low frequency spec and just generally aren't worth buying IMO (but here in US have been known to replace parts for free even after warranty, altho that may do you no good). Shadyj, our sub reviewer, mentions the Paradigm subs he's experienced, I'd take his advice seriously. B&W I wouldn't bother with for subs generally. Polk, Klipsch & Kef....meh, maybe one or two Kef models but don't really keep track of them. Not a fan of Rel but if priced right for the right model might be okay.
Most of what I can think of will be more limited to US. Rythmik might ship overseas, altho it may be limited to diy kits? It's been a while, check their website (rythmikaudio.com). Is that a possibility for you, diy or having someone build a cabinet for you?