Iirc, software takes the highest plus available, so six +1s wouldn't give a +6 bonus, just that base +1. This is what was stated in one of the earlier posts on computing in GH2 and I haven't noticed anything saying something else.
Anything with a computer component in it adds to the needed stats, data whatevers or otherwise. The bracelets and visors are the only comp 3 items in the base game, and the highest level computer you can buy without modding. Apparently there's one comp 4 hiding in one of the quests, but just one, and you have to kill someone for it.
It's pretty easy to mod in something useful, though. Like so:
Armharness 9
name <Nascent AI Core>
desc <A barely sentient AI system, waiting for instruction.>
Category <ELECTRONICS COMPUTER>
Factions <GENERAL>
sub
Computer 9
Computer 9
end
Which is bloody heavy, but gives you all the computer points you need in one comfortable ~$10k item. Wanna' take a guess teh what I did?