Disc brakes and seat post?

I've been out of WW loop for quite sometime and haven't really been up to date on any parts. I got a new frame, Turner Flux 08 on sale from Competive cyclist. Everything from my old bike is transferable except for the rear brakes and seatpost. I am XC rider who is weak on the climb but an aggresive downhiller at 140 lbs w/out gear. I am looking for performance first over weight. If something perform better at around 30grams heavier at the similar price then I'll choose the heavier components.

-The seatpost i'm looking for needs to be 27.2 400mm. My budget is 125 bucks. One that fit the bill for that is KCNC Ti Pro Lite Seatpost. The weight from Fairwheel is 143g for 27.2 350mm. What else should i be looking at?

Disc brakes straight out of the box at 250 bucks or less. I don't even know where to start on this since I've been using Hayes first generation disc brakes (12 years old). I'm looking at Hope Mini X2 Pro Disc Brakes claimed at 295g. Magura Marta SL Disc Brake 2009 claimed at 324g. Avid Juicy 08 Claimed at 345g (170 bucks at Jensonusa). Last and not least Formula Oro Puro Disc Brake claimed at 307g (I know its 300 bucks but willing to check it out).

Thanks in Advance.