As far as the LiteTrail cook kit, after shipping the T.E.A. system to you, the difference is only $22, so that is not to bad.
As far as the weight, the lid on the pot is 0.6 oz, simply use a piece of foil instead (which doesn't even really show up on a scale) and the total weight then becomes 2.3 oz. Still more than the T.E.A. system, but only by 0.7 oz, and again, there is the durability issue to consider.
Jhaura does source a thinner titanium for his cook pots than some of the others, but it is still very, very, very durable (especially when compared to a beer can pot). I have a number of other ti pots/mugs (including MLD, Snow Peak, Evernew and even another Toaks, but a different thickness) and I would say it is just as tough, especially since the 500 ml pot is so small. Really though, I wouldn't worry about the thickness, unless you are very hard/rough on your gear, which if this is the case, then you definitely don't need the T.E.A. system...