I have have had my g35 for two years now and my only issue with the car was the sound. I wish it had the same exhaust note as the stock coupe. On my mission to achieve this sound, I first got the Tanabe axleback. It looks nice and at first the muffler tips looked way too big for the car but I dont really notice it anymore, looks good. The sound is definitely throatier but still quiet in the car and that nice exhaust note can only be heard when you WOT. Then I got the R2C cold air intake with upgraded black hex filter but got them used from someone with a G37, I thought they would fit but there was no way to make them fit because our car only has one PCV valve while the new G37 engines have two. There was absolutely no way to make it work. It sounded great but I wanted something more reserved. I just installed the Mishimoto Post MAF silicone tubing because I like the idea of smooth intake tubes for less turbulent air for a more responsive throttle. There are other manufacturers like Z1 and HPS but I got the Mishimotos on Amazon for $90. I took it on a run and I can tell the car exhaust now sounds a little deeper, nothing crazy but good enough for me. The responsiveness of the car at WOT also does feel better to me. Not sure if it a mental thing but my engine does sound smoother. Next I installed the Upg8 dry drop-in filters. I never heard of this company but they are only slightly more expensive than Fram regular paper filter and these are washable, dry, high flow filters. I did not expect much for $15, but the fit and finish was actually decent, I have owned K&N and aFe filters for other vehicles and I would say Upg8 is on par with those. My car did breath a lot better afterwards and made the car a little louder. Now the exhaust notes is exactly what I wanted. I will try to follow up after putting a few thousand miles on these filters to really see what they will take and how easy it will be to clean all the particles out.