Mind Flayer base bab?

[jasper]

In the MM1 the flayer is +8 melee with his tentacles.
So if I give a weapon pro with rapier is should be +7 ?
Correct?
Cause weapon finesse use it dex bonus of +2 or is just +1
So base attack would be +6??

The reason I need this is I added classes to the creature and need the base.
Mr M.F. is made at the party for destorying his base of operations and what to learn more to whop up on the party.

Thanks

 

[the Jester]

Aberrations have a base attack bonus of 3/4 their HD, just like a cleric. So an 8 HD mind flayer has +6 BAB.

 

[Grazzt]

Mind flayer's base attack bonus is +6 (it uses the same progression as a cleric; all aberrations do).

Weapon Finesse (rapier) would grant it a +2 (for Dex) to attack rolls when wielding a rapier. So, using said rapier, its attack would be +8/+3.

(Remember, after +6 base it gains an additional attack with a melee/missile weapon).