Just a fun fact. You would need to roll 24 dice (so magic 12 and Attribute Boost 12) on an attribute test to get the +8 on average that the cyberlimb is giving you, would suffer hideous drain, and you couldn't do it anyway because the attribute boost is still capped by the aug limit.
Comparing an attribute boost of 1 to a +8 to agility is nonsensical. I'm willing to consider the comparison between +2 full body agility through cyber, bio or magic (even though it's not really a comparison because, well the +8 for almost any attack is a huge issue) becasue at Agi 7 an elf with +2 Agi could get to the same pools as the Agi 1(9) Cyberlimb guy.
Of course the cyberlimb guy paid 84K for that, where the elf paid a racial priority, 6 Attribute points, and either more money and essence or 2 full power points and an adept power point.
It's just a poorly written rule (or interpretation, the belief that the cyberlimb is not covered by the aug max is based on a reading that I don't think is the correct one) and a hold over of one of the most broken aspects of 4E.