Like I said the spare is useless with a BBK which is what you say you have. That's cool, I'm in the same situation and keep a plug kit and air compressor in the spare tire wheel well. Also good to have caa membership.
I just think that Nissan designed the spare tire to be roughly the same size as the OEM wheel and tire combo, so if you are dragging your pipes on the ground your current wheel tire setupis probably a lot larger than OEM diameter. So that when you switch to spare its smaller and brings you closerr to the ground. For example your tires may be too tall on a larger wheel.