1. I doubt you;d notice a huge difference....they're not massively lighter, and you'll have to buy a bash to go with as well.
2.In theory I guess so....it'll be on workmanship though i suppose.
3. Trialtech should be fine I would have thought,
In all honesty, I;d keep the trialtechs and spend the dolla elsewhere. If you run a king or pro2 and want to lose some weight..and know of some decent price middleburn cranks with a TI bash or TNN then i guess it'd be worth upgrading.