On page 165 of ArM5 it is stated that
Does "Aura Bonus" refer to the Realm Interaction table on p. 183 ? Because it isn't mentioned there.
Suppose you are studying one pawn of Infernal vis in a Faerie Aura of 6. What's your bonus and how many botch die do you roll ?
I would say a malus of 6 and 7 botch dies (1 for the pawn of vis and 6 for the foreign aura).
Am I misinterpreting the rules ?
Nicolas
Serf's parma, but yes - it refers to the bonus on the realm interaction table. But I take it to mean the modifier, which may be negative - poor wording.
So if you're studying vis in a Faerie aura of 6 you get a +3 bonus (half the faerie aura strength) - unless you've got Faerie Magic. You also get 6 more botch dice for the aura, but as for how many you get from the infernal pawn - that depends on the precise type of Infernal vis you are handling, per Realms of Power: The Infernal, if I remember correctly. And I'd add one basic botch dice for good measure, for a total of 8 and up. Not a particularly safe enterprise...
That's the one, aye. My take would be that although the vis is infernal, the act of studying it is not, just as using Infernal vis to boost a spell is not itself an Infernal art or act. As such, provided the Infernal Vis was used to improve an hermetic art, I think the aura interaction modifier would be the same as usual (ie. positive for an hermetic magus in a Magic aura) but that extra botch dice (one additional die per pawn used, I think, though perhaps more depending upon the type of Infernal vis as per RoP:I) would be called for.
Well, some theologians and my GM-evilishness will disagree... The end does not necessarily justify the means. Now, I only wish my players would try some of that infernally tainted ReVi combined vis I gave them 2 sessions ago... 
One issue though, as I see it, is that if you do apply the penalty, no player will ever do it more than once - the negative modifiers are too severe, and you also end up with such issues as infernalists not using Magic or Faerie vis because it's useless to them (relative arts scores being lower).
Depends upon how you play it,
If using Infernal Vis in this way is perceived as an "infernal activity", then perhaps you will benefit from doing it from within an infernal aura - now that doesn't sound so bad, and it gives players some incentive to spend plenty of time in nasty nasty aurad 
Well, I give them the bonus as if it's Magical Vis. But the usage is inherently sinful. Oh yes, and extra botch die, should a 0 come up.
I only wish my players use the infernal ReVi vis for their Aegis. Excellent way to allow every demon to enter the covenant! 