Just a little something a friend and I have been tossing around for a while now when discussing the School of Ramius. The rules for using Performance Magic with Martial Abilities are pretty clear, but what happens when someone combines Performance Magic with Subtle Magic? As far as we can tell this should completely negate the negative aspect of using a Martial Ability with Performance Magic since you no longer have to make all the gestures and what have you. Thoughts?
My thought... it negates the point of having Performance Magic: (Martial Ability). The whole point of Performance Magic, as I understand it, is that the gestures and words you perform as part of the ability take the place of the usual gestures and words for spellcasting. If you don't need to make any gestures, then having Performance Magic to cover the gestures the you don't need to make is pointless.
What you want is to be able to cast spells while wacking someone with a sword/axe/big stick... which is a laudable goal. 
I would suggest that instead of bothering with Performance Magic, instead you want Sutble Magic and Spell Mastery (Fast Casting) to allow you to fast cast the spell, without gestures, as part of your combat action.
I think this is addressed right there, page 29, Mysteries Revised:
[i]...It is the action... of the practice that (is) the focus of this Virtue, not the products of craft-working (i.e., the combat itself). An Ability that... is physical (such as hunting) replaces gestures...
...Words or gestures that are not being replaced by Performance Magic remain as normal mystical components of spellcasting: use the normal ArM5 rules and adjustments (including Virtues such as Quiet Magic and Mastery Abilities such as Still Casting)...[/i] [size=85](emphasis added)[/size]
So, Virtues (or Mastery) such as the ones you're suggesting only affect those aspects not replaced. It sounds like Subtle and a physical Performance are mutually exclusive (as would be a vocal Performance and Quiet/Silent), because they are being replaced by PM and so are necessary to the concept - a ritual performance (even if one disguised).
However, a mage could combine Physical Performance Magic w/ Silent Magic, or a Vocal Performance Magic with Subtle Magic - those seem fine by these rules.
(And for those who would argue "But it doesn't say you can't" - then why say anything at all? Giving specific permission for only part makes no sense if permission is valid for the whole.)
That's about what I thought.
Note that the main advantage of Performance Magic is that you need an Awareness roll to fast-cast defense against it. ArM5 p83 hints that Subtle Magic might require one too.
If you really want to do both a normal attack and some spell casting, you'd need to Fast Cast and this is not compatible with Subtle anyway. You could always invent a Minor Virtue that would allow you to Fast Cast through Performance Magic if that's what you want.
I realize p83 in ArM5 specifies fast-cast spells are always cast with bold gestures, but I've been assuming that Subtle Magic overrules that. Is that not the case?
FM
While we're on the topic of Performance Magic, anyone care to weigh in on the balance question for Performance Magic? I have a friend in a game we play who wanted to make a sort of martial arts magi. We didn't have Mysteries at the time, so the best we could come up with was Subtle Magic + 2xQuiet Magic so he could basically cast his spells as part of his "fighting" or Deft Art Corpus (which covered most of what he had in mind). Performance Magic seems much more on the nose, but from my reading of it, Performance Magic: Brawl (replace gestures with brawl) is basically strictly inferior to Subtle Magic (no gestures). Am I missing something?
I am not sure. The way I read it is "bold gesture == no gesture, exaggerated gesture is not affected." If subtle gesture would give the +1 modifier, it would be an open-and-shut case.
Use of non-Hermetic words/gesture makes it hard to Fast Cast a defense. If it's the same EF for Subtle Magic, then you are perfectly right.
Performance Magic is very good if both the words and gestures are mundane. Sorcerous Music is very powerful as you can either sing or use a wind instrument that can extend your Voice range. I would suggest house-ruling that Brawl (jutsu) can use kiai as the word component.
That would be my inclination as well, or to allow "carrying" attacks, although zeroing out is painful. Let me see, you get to use Brawl over Finesse for initiative, that's... maybe a win. You can maybe get a zero'd out defense roll from brawl, that's probably a win. You could also claim the "lets him maintain a spell without needing Concentration rolls." bit also means that if you get hit while doing Performance Magic(Brawl) it doesn't break your concentration, although I'm not sure I like that (not to mention I don't think that was the intention 
. I'd be more inclined to just give you a bonus on your concentration roll. Either way, sort of in the house rule territory, yeah? RAW it doesn't seem to be worthwhile in the least?
I'm not sure there is anything supports a mage doing something else while casting a spell. There may be nothing that specifically prohibits it in so many words, but I think it's implied in a number of sections. I just can't believe that, by default, a mage can be engaged in full combat and also cast a spell even with penalties.
That is what Performance Magic (Martial Ability) allows - and why it's at a penalty.
You sure can be engaged in combat and cast spells. You can even be wounded, and will need concentration roll if you were casting the spell after.
"Engaged in combat" and cast a spell: totally fine - if what you mean is that combat is happening around you, someone is swinging a sword at you, etc.
"Engaged in combat" and cast a spell: not fine - if what you mean is that you are swinging a sword back at someone.
Why not?
-> you will have to go subtle because no gestures
-> you will have to do a concentration roll because you are casting a spell while doing some other thing
The rules do not forbid that.
ArM5 p82, "There are some things ... impossible to do while casting." The list of Situations where casting is allowed are listed on the Concentration Table. Attacking isn't there.
Fast Casting seems to be outside that realm.
Thanks, and yes - when I said "engage in full combat" I meant the latter, to attack with a physical weapon (sword, bow and arrow, boot-to-the-head, whatever) while casting a spell.
No, no they do not. Specifically.
The rules also do not specifically forbid Lab Work while engaged in combat. One "Endurance of the Beserkers" with Duration:Season, and you're good to go - fight all season long, 24 hours a day, and still complete all that labwork. You could even spend most of the day fighting outside your lab, so long as 10 hours/day for 80 days/season are in the lab - I defy you to find any rule against that either.
In fact, altho' the rules say "There are some things it is impossible to do while casting", it never specifies what those are - so they must not be anything that would ever happen or be worth mentioning.
My work here is done. 8)
You missed the 5 Continuing Situations of the Concentration Table. For instance, you can have a conversation both before and after casting, but not during. 
I stand corrected, sir. You can fight, just not hold a conversation.
(But... by analogy, does that then imply that a mage cannot have a conversation during a season of Lab Work?)
(Altho', by some "reasoning", altho' those are in the "continuing" category it does not also mean they are in the "impossible" category. Just because pets are alive and a dog can be a pet doesn't mean your pet dog is alive - or something.) 
My thinking is that everyone can only do one action per combat round. So I can't swing a sword and cast a spell in the same round. (yes rules about fast casting and fast actions aside)
Using the same logic, you cannot have a conversation while eating. There's something wrong with this section.
Erm, it does but I get the gist.
I think this section and table should be taken out and shot. Like how is "Casting another spell" a continuing situation? Do you roll after 2 minutes?
IMS it is talen MUCH more generically. You can fight. It is not the exact movements that matter, but the fact that you are doing the activity known as "use single weapon t beat the crap out of someone" what is considered Performance Magic. If the moves need to be ritualistic we would be talking about another virtue. No PC uses it, but one of the major NPCs does have it related to storytelling. He does not need to tell the same story to cast the same spell over and over again.
YSMV 
Cheers,
Xavi