Posted: 11/11/2014 at 11:35
It is worth having the tools. Bike shops sell a range for different budgets and you can't really go wrong if you buy from there.
Two main types: ratcheting and beam. The ratcheting type will allow you to tighten the fastener to the chosen setting and then "click", at which point the wrench will stop torquing the fastener and rotate a bit. These are more common.
The other type (and my preferred type though less common) is the beam type. This will have two metal beams coming from the head of the wrench rather than one - one has the handle and a gauge plate, and the other has an arrow or indicator which lines up with the gauge. This type won't release at a given setting - you don't need to set it - you just apply force gently and increase until the tool is bending such that the value on the gauge is correct. Really simple, easy to see what you're doing, and you don't have to worry about checking you set the wrench up correctly. Park Tools sell one for smaller fasteners (TW-1) and one for a higher range of torques (TW-2). You'll want the TW-1.
Another tip is to make sure you get some carbon fibre assembly paste. This isn't like normal grease, but will increase the friction between the mating surfaces - this ensures the part stay tight together without needing excessive force which would crack a carbon fibre component. Multiple brands are available, I use this: http://www.wiggle.co.uk/finish-line-fiber-grip-carbon-fibre-assembly-gel-50ml/