I wanted to add to this tread, as there is some very good info in here.

The 2004-1007 Ion Redline and Cobalt SS used the P12 PCM and were 100% 58x. I am working on an E67 swap for my 2007 right now, and verified the reluctor wheel is 58x at a local machine shop where one of these motors is in for work. I had it in my hands, and it is not a 7x.