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I'm building a whip character, and one of the class features I get allows me to pick one exotic light or one-handed melee weapon that has the disarm or trip special feature and become proficient with it. I get this from the Magus archetype Spire Defender. I like the fact that the scorpion whip allows me to deal lethal damage, regardless of natural armor and armor, but its description confuses me.
A whip deals no damage to any creature with an armor bonus of +1 or higher or a natural armor bonus of +3 or higher. The whip is treated as a melee weapon with 15-foot reach, though you don't threaten the area into which you can make an attack. In addition, unlike most other weapons with reach, you can use it against foes anywhere within your reach (including adjacent foes).
Using a whip provokes an attack of opportunity, just as if you had used a ranged weapon.
You can use the Weapon Finesse feat to apply your Dexterity modifier instead of your Strength modifier to attack rolls with a whip sized for you, even though it isn't a light weapon.
Weapon Feature(s): finesse, reach.
Benefit: It deals lethal damage, even to creatures with armor bonuses. If you are proficient with both scorpion whips and whips, you can use a scorpion whip in either the normal way, as a typical light performance weapon, or as a whip.
If you are proficient with both the scorpion whip and whip, you can use a scorpion whip in either the normal way (as a light performance weapon) or as a whip. When you use a scorpion whip as a whip, it is equivalent to a whip, but deals lethal damage and can harm creatures regardless of their armor bonus.
Weapon Feature(s): performance (plus disarm, reach, and trip if you are proficient with whip.)
When wielding this weapon, if an attack or combat maneuver made with this weapon prompts a combat performance check, you gain a +2 bonus on that check. See Gladiator Weapons below for more information.
So what is the normal way of a light performance weapon, and how exactly does that differ from a whip?