Took the plunge and purchased the update...I am in QC, AZ. Update is great and I actually have streets in my area now. Had it installed at Superstition Springs for only 75.00.

 

So after my last appointment (when their compact flash drive connector was damaged), I was able to get the Nav update and the preset scrolling issue fixed today. Sewell Infiniti in Dallas only charged me $55 for a half hour labor for the nav update. I am happy to report that none of my songs were missing and all of my stored locations were still there for the maps. I'm very happy with both updates. I didn't notice any shifting issues caused by the ECU update, but I had just gotten out of a G37 loaner, which may have messed up my feel for my car's transmission. I have a lot of thoughts on the G37 compared to the G35, but that's for another post I suppose. So I think it's good news that nothing seems to be affected (negatively) by either update.