Originally Posted by Nillaz

You will need spacers. If you aren't going to make your own the ones from Zenclosures with a 5.75" center hole will be a perfect fit. Zenclosures Speaker Spacers

If you go with these be sure to make a note on your order that they're for a 370Z. One of the 3 mounting points for the spacer is pretty tight against the door panel and Mike will modify the bracket slightly to make sure that it clears it.