To continue with my mini review....One of the problems that I ran into with the T5 is the hook-up to my tube amp.
This particular issue came to my attention from another old timer a'phile, that happened to mention to me that IF I hooked up the REL as per the factory instructions to my ARC tube amp; that I would risk blowing up the tube amp

Why, because my ARC uses the 4ohm tap as a ground and is apparently a balanced design which would create a possible short if i hooked up the REL as per the factory recommendation and as i was doing with my ss amp. So, after calling the REL rep ( Sumiko) and the ARC rep, I was instructed to hook-up the REL in a different manner with the ground cable from the sub going to the 4ohm tap and the positive and negative ( left and right) connection attaching to the 8 ohm taps respectfully on the amp. With a little trepidation, I hooked up the T5 as suggested to the ARC and all is fine.....no explosions so far
To conclude, the REL T5, while being the smallest and least expensive of the new subwoofers from REL is IMO a real winner. With some fiddling, the REL T5 will most likely match with any small-medium size speaker and room. Highly recommended and not too pocket book unfriendly... a rarity in audio these days.