Shaft sizes are the same, I believe. Just need to check about the electrical connections. I'm having a block on whether they are the same basic electrical set up. I've had only a handful of Intecs in my shop, and never was dealing in a swap situation. Always was a same style swap or a rebuild going back into the same body. How the muffler works for the Ultra body might need a tweek on the tailpipe.
To be double certain, hit up a PM to Walt 2002, the man is a treasure trove of info also.