I did a search but did not find any inform on this.

Q1. My mum has a 2003 G35 sedan with the projector lights, she said I could have them and give her the ones from my 2004 G35 coupe.

Will the swap fit?

Q2. Has any installed the seat from the 350Z into a G35 coupe.

Thanks

Answer to question 1: No, the sedan has differently shaped lights. Personally, I like the coupe lights better.

Question 2: Not sure about that, im sure it is possible, but why would you want to? Out seats are much better looking, and I find them more comfortable. Anyway, good luck.

The G35 Sedan doesn't have projector lights. (Unless the halogen non-HID ones were projectors, I don't know)