What speakers will fit?

MaysEffect

So it seems. From the pics i've seen, the speaker looks like a 6 1/2 in a oversized adapter/spacer

This was posted in another thread years ago.

This seems to be the standard adapter across multiple nissan/infiniti cars.

If you have the Bose 6x9, a 5 1/4 would be an easier installation just by using a 6x9 to 5 1/4 plate adapter.

Where as this type you will need a adapter/spacer of unknown length. Most high powered drivers have a 2.5-3.5 inch mounting depth. The shallow depth drivers usually cost significantly more for the same total output (neodymium magnets, wider basket). They also inherently sacrifice a bit of bass impact because of the shallow cone depth.