deepakvrao, which of those parts aren't just a carbon layer on top of aluminum? Not that there's anything wrong with a little bling, but carbon-wrapped aluminum ain't full carbon -- likely more resistant to crushing at the expense of a little weight.

I got a bunch of stems on sale, many of which were carbon. All different lengths, too. For now, I've got one bike with aluminum bars and seatpost plus one of the carbon stems. A second bike has carbon bars, stem, and seatpost.

Between the two, I think that tires make a bigger difference in road feel.

As far as torque goes -- my stems are all Easton, an EA90 alloy and some EC70 carbon. The torque markings on the EA90 are 4 to 5 Nm; the EC70s are marked for up to 8 Nm. I'd say that a torque key or wrench is more important for the alloy stem than for the carbon ones.