Help figure out a CR

[Crothian]

If you could please, I'm trying to figure out the CR for a creature. I've taken the Legendary Tiger (it's in the ELH, MM2, and maybe even MotW). Normally it has 26HD and is CR 10. I've advanced it to 48HD but I also need it to change from animal to magical beast. So, that makes its BAB for instance just a bit better among other things. The stats stay the same excepot for the Int which basically is a 14 now. Any idea what the CR for this thing should be?

And just for fun, what would the CR be if I gave it maximium HPs?

 

[Crothian]

The CR rules can't be that complicated, can they??

 

[trentonjoe]

If you could please, I'm trying to figure out the CR for a creature. I've taken the Legendary Tiger (it's in the ELH, MM2, and maybe even MotW). Normally it has 26HD and is CR 10. I've advanced it to 48HD but I also need it to change from animal to magical beast. So, that makes its BAB for instance just a bit better among other things. The stats stay the same excepot for the Int which basically is a 14 now. Any idea what the CR for this thing should be?

And just for fun, what would the CR be if I gave it maximium HPs?

sooooo

you are talking AC 25ish
3 Attacks at +50ish?
Damage around 15-25 a pop?
hit points 350?
Just guessing here.

48 HD 15
max HD 16