Can any body tell me the difference between the FSA head set and the Chris king head set offered by iro cycles?

Why is the Chris King headset 100 dollars more?

Also why are there difference lengths off for the crank set? what is 5 or 10 mm gonna do?

the chris king headset is a much higher quality headset in terms of durability and sealing, but its higher quality than most people need. you should be fine with the FSA.

the crank length is the length from the center of the axle to the center of the pedal spindle. most road bike ive seen have 170mm cranks, and most people running fixed that ive seen have 165mm cranks.

the shorter crank arm effectively keeps the pedal higher off the ground, reducing the chance for pedal strike when taking corners (since you have to keep pedaling when cornering, this is a much bigger issue on a fixed gear than on a freewheel).

Sort of... crank length is also important for positioning your pedal under your knee when you're pedaling, which gives more power and less stress on the joint. ostensibly, taller people are going to want 172.5 or 175 cranks to compensate for their thigh length, but it's different for different folks.

You also get a lot more leverage and power with longer cranks - I definitely feel the difference climbing on 170s vs. 165, and MTB people can use up to 180mm cranks for powering up hills or over logs or whatever it is that they do. But as mentioned the pedal is going to be closer to the ground -- not a big deal on most track bikes, potentially a problem on conversions with lower bottom brackets.

Simple answer: The Chris King makes you faster.

King = sealed bearingThe King is definitely stronger but not worth the $$. I use a FSA Pig DH Pro which has sealed bearings and is about $80+ cheaper than a Chris King. Read the reviews on MTBR.com.

There are two reasons here. One your cool points go up (there is a direct correlation between cool points and speed), and your wallet weighs less

Don't forget that your empty-headed consumerism reduces your weight at the highest point in your body, thus further lowering your overall weight AND your center of gravity.

See being away from Toronto for a month and I'm already missing major points.

*shakes head slowly and walks away into the nigh..morning*