We had a thread on mirror adjustments once a long time ago. If you switch over to a different way of adjusting/using your mirrors, you can eliminate the blindspots in the nearby lanes. It takes some getting used to, but it's basically this style of adjustment:
How to Set Rear . When you do it that way, even on the Z, a car passing you on either side is always visible as they move from rearview to side mirror to visible through the window directly.
The downside you have to pay attention to is that there's a new blindspot behind you a little and 2 lanes over. So under this setup, don't trust your mirrors for a full 2-lane change. Re-check after a lane if you haven't looked manually.