--come on over to the peripheral neuropathy forum:
http://neurotalk.psychcentral.com/forumdisplay.php?f=20
--there are at least two CIDP sufferers over there (one who is on IVIg), and others with "idiopathic" diagnoses that have tried that therapy, who can share with you.
And, you'll learn a lot just looking through the useful websites section at the top, and through the other postings.