Yup, all B-series flywheels are interchangeable. The only parts which are not interchangeable are clutches--all '92-up B-series use one type of clutch while '88-'91 use another.

If you can get the ITR flywheel for a really good price then I'd say go ahead with it, but otherwise you can get an ACT Xact Streetlite flywheel that weighs 12.5 lbs (I believe ITR is 14 lbs) for $225. That's light enough to be noticeable but not so much that it really becomes a chore to drive.