I am a bit late to the party it seems

I dunno, they state you can have a max boost of +4 to a stat... regardless of where is comes from...
The +4 you are thinking about is a rule that only apply to augmentations (cyberware and bioware) and is mentioned on SR5 p.94
That mean all augmentations (cyberware and bioware) are automatically affected by this rule (they don't have to explicit mention the limit, most of them don't, and still be affected by it) - if they want to break out of the rule they need to explicit state so (which for example the wireless bonus of wired reflexes do). It also mean that no magical enhancements to attributes are automatically affected by this rule and if they want to use the same rule they explicitly have to mention it (as you noted a lot of them do - but not all of them)
Drugs are not augmentations (cyberware or bioware) and they also don't explicit mention this rule, thus they are not affected (but if you combine drugs with say a magical enhancement that does use this rule then the magical enhancement will get weaker to compensate for the bonus you get from the drug so that you don't exceed the limit).
The question raised by Aaron's reading of the text in Wired Reflexes is whether, for instance, you can stack Wired 1, Nitro and Increased Reflexes to achieve +5D6.
Sure, that will be legal.
For the purpose of initiative - wired reflexes is only incompatible with other augmentations (cyberware or bioware), nitro being a drug is compatible with everything and increased reflexes are only incompatible with other increase reflex spells. This is one of the strengths with wired reflexes.
...but you can't for example use synaptic boosters (which is in other cases superior to wired reflexes, at least at rating 2 and 3) to do the same as it is incompatible with any other form of initiative enhancement (which include augmentations, magic and even drugs).
You can also use improved reflexes and drugs to get more than +4 reaction (as the reaction part of improved reflexes is compatible with everything).
If you want to continue to discuss this matter I would be happy to do so, but in that case I suggest that it is done in this thread:
http://forums.shadowruntabletop.com/index.php?topic=12756.msg235023#msg235023Thanks in advance
As for the topic at hand.
Would like if someone official could state something. anything.
It's been very quiet for a very long time now.
Even Aaron stopped posting
