Are subtle upgrades such as lighter tires and exhaust worth the money?

[TheFinalBoss]

Good afternoon everyone. New member here looking for some advice. Let me start of by saying I currently drive a G37 Sedan. I really wanted a Z, but I needed passenger seats and a bigger trunk so I ended up purchasing the next closest thing. I finally paid off the car and have some money laying around to customize my car and make it more unique or a little bit better than the rest of the crowd. I was planning on getting some 17 inch Enkei RPF1s in black for my first upgrade. I read that they are lightweight and have the ability to make the car perform better and get a bit better fuel mileage. I also love the looks of the RPF1s compared to the rest of the Enkei line up. My next upgrade would be exhaust. I really want the HKS exhaust because I read it will also reduce weight and improve the flow which would give better performance. I also read they are not too loud, and has a smoother sounds. I was thinking of getting CAI later on and maybe a light weight battery. I also live in sunny California, and was thinking of trying out some summer or sticky tires instead of my all season Yokohamas. Do you all think these upgrades are worth the money? The rims and the exhaust itself will be at least 2k. Thank you all for your time, and I am looking forward to your replies.