2 Subwoofers or 1?

I don't think two of the T/9x are in budget....

I hear you. You really want two subs, front firing, located near your little stand mounts. You will be crossing over fairly high and the subs will make your imaging work much better. The smaller sub does not go that low but I'd take two of those over one of the others. You can get the two small subs first then get a larger single sub to work the very bottom frequencies some time in the future. 

Three are better.

Regards,

Dan

I have a similar room and have 3  S510 subs so IMO given the 2 choices I would  say neither...the  5tx is bottom firing and I wouldn't want that at all,and 1 9x is not enough...I would wait till funds permit and then buy  2  7X or 9x...or 2 used Rels like the previous I series

A subwoofer/s system is a separate component which are more often designed to accommodate most future speaker or room changes.

For the sake of a direct comparison does this dealer represent any other subwoofer manufactures?

Many. It's Audio Advice in Raleigh. Audioadvice.com. This is my first time thinking about subwoofers, so I am really starting from scratch. I appreciate all the advice.

Howard