Get the VQ sear and call it a day--or have a handy 'smith do an action job for you. The factory sear only takes minutes to modify to be just as good as the VQ.
The hammer is pretty much a waste, and won't improve trigger pull much (or at all!). Though it does have a "speed hole" for reduced lock time.........
The trigger is a good buy for getting rid of pre and over travel--however, the factory trigger is already has an overtravel screw installed, and the aluminum trigger is incredibly easy to drill and tap for a pre-travel screw.
These are accurate pistols that shoot very well with minimal investments. Lots of info can be found online.
I'm not a fan of the hi-viz sight...not a great choice for target work and it is a bit large for my taste. I replaced mine with a 1/16" marbles bead sight.