A cyberlimb starts with an availability of 4. It has three stats: Body, Agility, Strength. Assuming you're human (best case scenario for this example), you're max in all three of those stats is a 6. When you buy a Customized Cyberlimb, it starts with a 3 in all three stats, and you must increase them individually, with each addition adding a +1 to the limbs availability. As a human you can actually start with a Body 6, Agility 6, Strength 5 customized limb. You're only losing one point from your strength here. Any other race, you're going to have to sacrifice more in some areas to get other areas at there cap.
Now, you could ask, what is the advantage of having my strength/body that high on the limb. Strength of 6 is useful in that it gives you a point of natural RC with that arm. Body being maxed of course helps increase you overall body (an average of each limb plus your torso's rating). You could slap in some strength enhancement, but you'll probably want to save that for more agility/armor/goodies.
In your example, I would highly suggest alphawaring the Wired Reflexes 2 over any of the limbs. On a similar note, Biocompatibility:Cyberware can really help out.