Somehow I get the feeling that I'll be able to use the rear side window, as I usually have the seat back or reclined a bunch. In my Miata with the soft top up, I have trouble seeing to merge. Hardtop has zero visibility issues though as I can turn my head to the LEFT and see out the rear window to the lane NEXT to me.
Hoping the BRZ isn't bad bc with good visibility you can weave in and out of traffic- I mean DRIVE SAFER.