OKAY, that's fucking BS right there. Synephrine is an agonist for a different receptor than ephedrine is. It has a much more negative effect on your blood pressure than ephedrine does.
If it didnt, then why did all products have ephedra in them until the ban happened?
Here's someone explaining it better:
http://www.philkaplan.com/thefitnesstruth/synephrine.htm
Anyone wanting to take an ECA stack needs a good understanding of alpha vs. beta agonists and the different receptors within each group.