Since you do things like add special ac bonuses to CMD and attack bonuses to CMB...
If you make a trip or what-have-you in place of an extra attack from having a high BAB, do you count your BAB as 5/10 lower for that maneuver? Or apply the -2 if you're using two weapons and making the maneuver in place of the extra attack?
If you're using a finesse weapon to make the maneuver and you have weapon finesse, do you use your dex in place of your strength to determine CMB?
If you have weapon focus in say a trip weapon, you add that +1 to trips with that weapon? How about a normal weapon?
Core Rulebook, Chapter 8, pg. 199: PERFORMING A COMBAT MANEUVER says it depends upon the combat maneuver, and you need to look up the specifics.
Core Rulebook, Chapter 8, pg. 201: TRIP says it takes the place of an attack. Which means, if you have a BAB of +6/+1, you make your primary attack as normal and then the trip is your second attack at the - 5 BAB.
Even if you are using two weapons, the rule above still applies.
Yes, if you have Weapon Finesse and are using an applicable weapon, you use your DEX in place of your STR to determine CMB for attacks with that weapon only. Your other weapon, if not a finesse weapon, still uses STR.
If you take it in place of one of the iteratives then yes, you take the -5 or -10 penatly on the CMD as well. Yes you also take the -2 for TWF if you do it in a round where you emply TWF.
Some CMs can only be performed as a standard action though, in which case you'd take your full BAB and no -2 for TWF either
Yes, weapon finesse works if the manouver can be done with a weapon. Usually only trip, disarm and sunder are done with a weapon.
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Yes, weapon focus, masterwork and magical enhancement bonuses all apply if you're using a weapon.
Some CMs can only be performed as a standard action though, in which case you'd take your full BAB and no -2 for TWF either
Correct. And these are specifically listed in the descriptions in Chapter 8 for each Combat Maneuver.
Bull Rush = Standard action
Disarm = Melee attack
Grapple = Standard action
Overrun = Standard action
Sunder = Melee attack
Trip = Melee attack
Feint = Standard action
I'm sure there's more in Ultimate Combat, but these are the normal ones listed on ppg. 199-201 of the Core Rulebook.
UC actually adds a couple of feats (Quick Bull Rush for example), that allows you to make those in place of a melee attack as well. (Only your highest though, so no 5 tries to bullrush someone)
They however need the Improved feat for that manouver first, PA or CE and BAB +6
Noted. Indeed it's not. I sit corrected.