What about infected I would call that racial.

Being infected is a magical thing though. They gain their power of increased reflexes through magic. I think the spirit of the rule is that the quality isn't compatible with anything else that raises initiative. That said, if you are saddled with being infected through game play and you've made it that far with just the Lightning Reflexes quality to boost initiative, I wouldn't take it away. I just wouldn't let someone start play with an infected that has this quality.
Why? Because if you get infected after the game starts, that's my choice as GM to inflict on the player. I'm not going to penalize him for something that is out of his hands.

I believe the intention is that Initiative Dice never stack. It seems overkill to me, since there is already a hard cap on Initiative Dice (5)... But I am pretty certain that is the intention.

Now, as Mantis said, GM ruling trumps all. But in creating a character for a game unseen, I would assume it won't stack.

That way you could be pleasantly surprised if you find out otherwise.

i'd say just give the higher of whichever initiative benefits them most (that is, if they gained initiative that is better from becoming infected, they'd use that. if not, they'd use lightning reflexes... sure, they paid for lightning reflexes, but if they just gained better initiative as a result of being infected, they're still getting the thing they bought). i don't own the book for 5e rules on becoming an infected to check, but if there's a karma cost to become an infected, i'd say give them a discount on it because they already paid for that part of the power.

then again, i would also generally not turn someone into an infected and have them keep playing the character at all... it's basically the same as if a vampire just shoved a sword through your skull, except now there's an NPC out there who used to be your character...

Personally, I wish they just had some good general rules about combining initiative enhancements, rather than tacking on these little blurbs at the end of individual initiative boosters. I understand if they want to cut off people from combining two or more cheap boosts to get the equivalent of a more expensive boost, but there are too many vague areas, and it is an approach that leaves loopholes. The increase reflexes spell and the move-by-wire system are compatible, and that's a very powerful combination.

Is this something they added for 5th ed? Cuz they aren't stackable in 4th ed. More likely a copy/paste error since that seems to be their go to method for bringing things forward from 4th ed. Well, that, and making sure they don't copy the whole thing, just enough to confuse the hell out of people.

Probably not. However, that remains to be seen. Since the errata team is still focusing on the Core book, and primarily Combat only, it may be quite some time before we know for sure.

So there is a cap of 5D6 for init.
Only way I have seen to meet but not exceed that limit is a Technomancer with an echo incress, I assume there are others. Most of the init bonuses say they are not stackable.

Is there others besides the one listed about move by wire and a spell?

The spell also works for reaction enhancers and/or wired reflexes (but not for the synaptic booster, which has more restrictive wording on what won't stack with it). Shapeshifters (in animal form) are a grey area. The books are mum on how their animal form initiative boosts do or do not stack with other increases.

That has always been the biggest weakness of mundane characters - magic doesn't just give comparable boosts; it gives boosts that often stack with augmentations. An adept face can have tailored pheromones and authoritative tone.

That is one of the reasons I asked about infected.

If I had to guess about the rules as intended, I would say they were trying to make the quality incompatible with any other initiative boosters. Unfortunately, while "This quality is not cumulative with any other Initiative enhancement,"is cut and dried, trying to be emphatic with the addition of "be it technological, chemical, or magical" opens it back up to questions as to whether infected or shapeshifter initiative improvements are magical or natural, with the latter letting it stack.

At the moment, it really is a GM call.

Yup

For me, the part I'm more concerned about is whether the initiative from infected or shapeshifter are considered "enhancements" or not. I say no, because it isn't something that is being added to the character, it is a part of their core being. Particularly for Shifters, as they aren't a modification in any way. I could see arguments for Infected being a mod, but that would be like saying that a SURGEd Changeling with Celerity or Satyr Legs counts as having leg mods. It doesn't, Celerity even specifically calls out that it is incompatible with leg mods and separately mentions that it isn't compatible with Satyr Legs.

Lightning Reflexes are so ridiculous expensive and yet so limited that I see no reason to limit them any further.

I allow them to be compatible with natural Ini from Infected, Shapeshifter and Shapechange as well as drugs. Because... why bother otherwise?

Drugs would probably qualify as a chemical enhancement, which is specifically called out in Lightning Reflexes as a no-go.

Yeah, that's why I have to allow it.
Banning drugs makes no sense anyway: Cyber/biotech replaces your existing nerve tissue, so it is reasonable that you'd lose the benefit of your natural reflexes. But drugs just open up your natural potential: Someone who is faster without drugs than the average person should be also faster when both of them are on drugs.

Or arguably someone with Lightning Reflexes happens to have the natural elevated levels of certain chemicals, hormones, brain stimulation, etc that the drugs induce, and the drugs can't push them much farther.

In other words you can always find an in game world reason. From a play balance perspective, the intent is clearly to avoid people relatively cheaply combining a number of +1d6 bonuses to achieve the same effect that normally would only come from being alt-indie on one enhancement path, at great expense.

So to me the question is: is this solution strong enough that most people would prefer it to an equivalent level of wired reflexes or adept improved initiative? If so, then it is going to warp the game away from the way that it is described, and you should tread carefully.

I was looking making a goblin, the lightning reflexes would stop me from getting regeneration. If not then I take regeneration and adept
Improved Reflexes. What is also not compatible with goblin but I could crank them up.

A would be a stealth char.
B would probably be a combat char.