High Level CR adjustment. Help.

[Dragonslie]

So I want to create a great wyrm red dragon that casts as and OBTAINS WIZARD special abilities. (for flavor reasons)

question. If i transfered all of its sorc CL INTO wizard CL and allowed it wizard sp abilities (NOT extra feats just school powers, bonded item, or familier)

What would the increase in CR be??

[vuron]

Honestly my initial reaction would be to say no CR change (if we assume sorceror/wizard are interchangeable) that being said the other class effects do result in a power increase so I would suggest a +1 CR.

Anything more than that is unwarranted.

[Dragonslie]

Just checking because I have the APG and was intending that the red dragon be an ABJURE using the counterspell sub school.