You may not need it. I don't with my 2109s & I have a little more weight. I added 2 6 volt batteries as well. However, I don't load much in the TT.
Oops, ignore me. I just noticed that you have the V6. I have a little more truck - doesn't fit in my garage either.
2013 Rockwood Mini Lite 2109S
2010 Toyota Tundra 4WD