The 210t hasn't been made for a while, but the current xst speakers are a lot closer in characteristics than the xlt. Theoretically they'll have better low end, but that usually has as much to do with enclosure design than it does with speakers.
It's always an option (and cheaper) to simply have the speakers reconed by a qualified tech. I don't think you'll get a recone kit from Eden for a T cab anymore, but a good solid recone will eliminate the farting.
You may also want to post this up on the Eden user forum. There's a lot more knowledgeable people there that can be of more help.