Looks to be as feasible as its kissing cousin, the XT225's, tank installation on a TW.
I installed a OEM metal XT225 tank without any issues following guidelines I found using "Search" and "Similar Threads" on this forum. However the TTR doesn't get much mention here so I have no real knowledge.
The 2.6 gallon capacity does sound attractive.
I would be tempted to try it with the understanding that getting the TW side panels to fit up against the plastic tank might require creativity. For instance I have piece of soft copper wire lightly tying together and pulling in the pointed tips of left and right side panel on a 4 salon plastic tank equipped TW. This keeps my pants from snagging on any protruding plastic.