Louder exhaust...

G37 isn't that quiet. Trust me

Has anyone used FatMat Sound Deadener? It's less expensive then Dynamat.

I put conny DWs and dynamat in all through the hatch (I went overboard). I have berk HFCs and Catback and the dynamat definitely cut that down from frigging LOUD to just frigging awesome. However, road (tire din) noise is still pretty bad. I track my Z, so I don't want to add any more weight by going crazy with dynamat, but I'd say a bit in the hatch is a good investment. BTW you do not have to "carpet" the whole hatch with dynamat. It is just intended to change the resonance frequency of the panel you are working on. A bit in the middle of any resonating panel is all you need and can save substantial weight. There are better sound deadening solutions (fatmat) that insulate from noise. really it is a two step process
1. Dynamat on resonating panels (just tap them to see if they "ping")
2. Dynalineror equivelent to insulate from outside sound. Dynamat.com | Dynaliner Brand
3. Next step is probably tires and perhaps bushings. I've run OEM, Pilot Super Sports, and Continental DWs. Don't kid yourself, none of them make the Z quiet.

After trying all this (actually I have not swapped out bushings...) I now just stuff in some earplugs that I get from work (I'm a pilot). I can crank the Bose up to 25 or so, and cruise in style able to actually hear my music. I only wonder what the neighbors think when I thunder by with my stereo cranked to "11" and my berks screaming at all the local liberals.

I've often wondered if going up a tire size would make any difference?
Like going from a 45 series to a 40 series on the front and a from a 35 to a 40 on the back.
I know most will think it would look like tractor tires but just wondered if more sidewall would help those of us that are not racing/tracking etc.

I don't care about being lowered or hellaflush or any of that obviously. ;)

just wondering... I don't know if it's even possible to fit those anyway.

I did GT mat in the hatch and doors during my stereo install and it made a huge difference in road noise. I did the whole hatch & all of both doors. I think what really made the difference was adding GT mat over the rear wheel wells. I hated the "ting" sound that every rock on the road made being thrown up against the rear wheel wells. I used two layers of GT mat over the wheel wells and that sound has been almost completely eliminated. I didn't notice as much difference in sound reduction when I did the doors, but my stereo sure sounded a lot better. I also switched to Michelin PSS and they run slightly quieter than the Bridgestones but not a whole lot. I was hoping the Michelins would run a little quieter than they do, but they do help reduce noise slightly. One last thing that helps reduce noise in the hatch area is using the factory carpeted mat. I ran with mine in/out quite a bit while installing the stereo and noticed less noise with the extra carpet pad installed.

I used Raammat sound deadener and their insolite foam mat on top in the hatch and doors. I had extra so I went a little overboard in the hatch but I'm pleased with the results. I wasn't trying to make the car quiet (the Z will never be quiet) but rather make the car sound and feel more solid, and it did just that. Driving over rocks no longer makes the 'ping' noises and the stereo sounds much better. I did this back in 2013 and have since added an exhaust. I think the deadener really helped cut unwanted vibrations in the hatch floorpan as well.

I used the same combo. I still need to do the doors, but doing the back half of the car made a big difference. It's the foam on top that does most of the work.

How did you guys do the clips holding g the wires? Did you cut or just cut and paste around?

I wouldn't count on tires making a difference but softer bushings probably would. (And less expensive.).

I cut holes in the dynamat and used OEM clips right back in

If you want to make your car quieter, you'll have to use sound blocker on top of the sound dampener. I used second skin damplifier and luxury liner on top of that and I got nothing but good thing to say about it. Just a warning though, the luxury liner is extremely heavy.

Same here. Mostly cut a slit in the GT mat and worked it around a wire or plug. I didn't remove many plugs. It worked well and the GT mat sealed up and stuck very well around all the openings. It was really easy to work with.