I learned of Sovereign Grace Ministries through another forum and when I visited their website I read:

"We describe our doctrine as being essentially Reformed, yet including a commitment to charismatic practice as biblically defined."

I thought to myself, Now that's interesting. I am not aware of any other charismatic Reformed group in existence...although I'm sure there are others out there. Seems to me that the theologically Reformed folk would want the genuine article and not stay around, and the charismatic folk would not want the restraints placed on their practice by Reformed theology. So neither group would be content and eventually your church would empty out. But somehow these people are pulling it off...and growing.

I think you are following the right path by not making the charismatic issue a point of division with your friend. Like you, I don't agree with charismatic theology and practice, but most charismatics I know hold to essential Christian doctrine if not Refomred tradition and theology. I consider them brethren in Christ but I don't really want to go to church with them.