QUOTE (Karoline @ Dec 4 2010, 09:03 AM)

The rules state very plainly "You can never have a stat above your augmented maximum." and possession fails to state any kind of exception to this.
Nitpick.
QUOTE (SR4A p.68)
Care must be made to distinguish between natural, unmodified attribute
ratings and those augmented by cyberware, bioware, adept powers,
and magic. Generally, augmented ratings are listed in parentheses after
the natural rating, such as: 4 (6).
The rules state very plainly that cyberware, bioware, adept powers, and magic cannot increase a stat above it's augmented maximum. For some reason, drugs & similar are not included in the augmented maximum,
Rules as Written.
QUOTE (Dakka Dakka @ Dec 4 2010, 12:00 PM)

Possession does not break Attribute maxima, but we are never told, what the maxima for the combined entity of spirit + vessel actually is. So effectively the don't have one. I agree that it may be unbalancing to use (vessel racial max + spirit Force ) X 1.5, but nowhere does it say that the maximum for the combined entity is equal to the augmented maxima of the vessel.
QUOTE (SR4A p.68)
The standard range of natural human attributes is rated on a scale
of 1 to 6, with 3 being average. Physical and Mental attributes have a
maximum natural rating of 6 plus or minus metatype modifiers, depending
on metatype (p. 81). The maximum augmented attribute value for
each metatype is equal to 1.5 times this figure, rounded down (see the
Metatype Attribute Table, p. 81). This also applies to Initiative.
Side Note: Apparently, only metatypes have augmented maximums. If the spirit is possessing a chihuahua, there is no upper limit to what it's attributes can be.
QUOTE (Dakka Dakka @ Dec 4 2010, 12:15 PM)

The rules don't actually say that. A new entity is created with physical stats equal to stat vessel+stat spirit and the spirits mental and physical attributes. The new entity is controlled by the spirits mind unless channeling is used. this new entity is different from either the spirit alone or the vessel alone. As such we have no clue what that entity's maxima are.
QUOTE (Street Magic p.102)
POSSESSION AND VESSELS
When a spirit possesses a vessel, the com-
bined being that results is dual-natured, has
Immunity to Normal Weapons (p.283, SR4),
and boasts all of the spirit's powers and skills.
Occasionally a possessing spirit's nature mani-
fests through the vessel in an effect similar to
a shamanic mask (p.168, SR4).
Combined ≠ New
Even if an entirely new being was created, possession modifies Physical attributes instead of using a "new" value (see below).
QUOTE (Street Magic p.102)
Living Vessels
If the vessel is a living creature, the spirit's
Force is added to the vessel's Physical attributes.
While possessed, the spirit's Mental and Special attributes are used (which means that a pos-
sessed technomancer cannot access Resonance),
with Initiative recalculated as normal (use the
spirit's normal Initiative Passes). The spirit is in
full physical control of the vessel but does not
have access to the host's knowledge, skills, or
experience. The mind of the vessel remains in
whatever state it was when possession began;
if conscious, it becomes an impotent witness
locked inside its own body for the duration.
Added to ≠ Replaced
The effects of Possession are magical in nature (paranormal critter power), and increase (not replace) the Physical attributes of the vessel. There is nothing allowing this to be an exception to the rules on Augmented Maximums. As such,
Rules as Written, the Physical attributes of a possessed living being are subject to that being's augmented maximums.
Mental and Special attributes, on the other hand,
are replaced with those of the possessing spirit, and as such are
not subject to the vessel's augmented maximums.
Just to clear up my position on the matter. What I have stated above is
Rules as Written. It is not, however, the rules that I use.
In my games, the attribute augmentation provided by Possession is
not limited to the vessel's augmented maximums. This is in addition to a few other important adjustments to spirits (modifiers to the functionality of Hardened Armor & Immunity powers, and using (F÷2, Round Up) instead of (F) for Physical & Mental attributes).