I got 6 1/2" speakers to replace the rears, and found they were the wrong size -- looks like 6 3/4" is the actual size. I made them fit, but I'm not proud of the result. I'm curious as to how others dealt with this problem -- did you get 6 3/4" inch speakers, or did you use some kind of mounting kit?

 

what kinda of speakers? I got 6.5" kappa's and they fit perfectly, used stock screws to hold it in place.

 

Wow, I guess not all 6.5's are created equal! I was in a rush to get these speakers and put them in before I left for a trip, so I went to a local car stereo shop where there wasn't a huge selection. I got some Eclipse 6.5" speakers that seemed decent. I was hoping to put them in with the stock screws, but they didn't fit at all. I then remembered seeing on the Crutchfield site that the 350Z uses 6 3/4-inchers for the rear. I went back to the shop but they didn't have speakers of that size or any kind of adapter kit. The guy gave me some Dynamat (no charge) and told me I could seal it up nicely with that. I got it to work, but the results weren't that professional. Well, at least it works and looks totally stock with the cover in place.

I wish I had known about the Infinity Kappa's fitting perfectly! I did so much research before putting in the fronts and the head unit, I guess I got cocky and just randomly got some speakers for the rear. Guess I should have done my research first.

Thanks for the info: maybe some day if my rear speakers work loose and start rattling or something I'll rip them out and put in Infinity Kappa's.

 

I put a pair of JL VR650 6.5" in with no problem. Have never heard of anyone needing 6.75" speakers for the rear, or having problems mounting 6.5"'s - very strange