REL T/9i or S5

Looking to add a subwoofer to my system in an 11 by 18 ft room.
For those familiar with the REL line is it worth it to spend the money on a new T9i or move up to the S series and buy a used S5 with the intention of adding another one later?
Right now the new S series is beyond my means.
Pair of used S3 will outperform T9s. I have the S3 SHO and it blows away the Strada lll I had before.
Thanks for all your responses. I'll be getting something in the lower end of the S series.
Rythmik F12. Save yourself some cash and get a superior product. I was a REL owner. Switched to Rythmik and have zero regrets.