As others have already touched upon, a good trigger is critical to getting the best possible groups -- and you won't find "good" on any trigger that comes directly from the TC factory.
As to the other items, I can tell you this: most (not all, however) of my rigs do have a 1x hinge pin, and that's because I am a stickler for precision. As an example, my 7mm Bullberry shot beautifully when I first got it -- and the groups would make most shooters drool with envy. But the 1x hinge pin made it EVEN BETTER. For some, the improvement would not be worthwhile; to me, it is.
But every frame/barrel combo will not necessarily benefit from the pin. Lastly, you do have to exercise common sense. If you begin to insert the pin according to instructions and see that it will take excessive force, STOP. You don't need the pin! I know of at least one individual who beat his frame to death and then blamed the maker of the pin.
Also, I had a factory Encore 6.5x55 barrel that was picky about its loads and would tend to shift POI from day to day. Getting rid of the rynite forend and adding -- you guessed it -- a 1x hinge pin made all the difference in the world. In fact, some loads that I discarded during development now became keepers.
But back to the kits: the most vocal opponents, as a rule, are those with the least amount of experience, and they'll never substantiate their disdain with anything concrete. Whether it's from a simple lack of understanding the basic concepts of the TC system or fear of the unknown, some folks just won't open their minds to anything different.
This is much like the Bergara barrel debate.
In short, the best advice I can give you is this: Take everything you read with a grain of salt and then make up your own mind.
