I have an 03 coupe with the standard (non-Brembo) brakes. I would like to upgrade them next time I have to change them. I was looking online and found some calipers that are 4 piston but I am very confused.
here is an example of some that I found:
https://www.ebay.com/itm/2x-Brake-Calipers-for-Infiniti-G35-2004-Nissan-350Z-2003-2009-Front-Left-Right-/164279620002?mkcid=16&mkevt=1&_trksid=p2349624.m46 890.l6249&mkrid=711-127632-2357-0

my questions are,
-why does this say it will fit 04 but not 03? Isn’t it the same thing? The brembo calipers say they fit 03-04 so why won’t these??
-are these the same size as stocks but just more pistons or are they actually bigger too
-will it fit in the brackets I have now or will I need more equipment (bracket, rotors, etc)

Those are pictures of rebuilt Brembos.

EDIT: They've just been sandblasted so they aren't gold colored anymore.

oh lol okay
so it will fit even though the listing says it won’t ?

If you scroll down under their compatibility chart it does say 2003, the title however does not.

Keep in mind if you're Brembo swapping you need a LOT more than just calipers.

Can you elaborate on this? We just put a set of used brembo calipers on my son's 06 G35 and we having trouble getting the pedal high and firm. Don't think it is air in the line as it isn't spongy and it gets firm with a quick pump. Please don't tell me we need a new master cylinder too!

It's a nonstandard bleed order on the calipers, make sure you follow the correct order. If not you can get a spongy pedal like that. Probably though there's air somewhere in the system, I strongly recommend a motive bleeder for doing brake bleeding.

As for what else is needed for the swap, rotors, brake lines, dust shields, typically also the master cylinder since it's a higher volume unit to handle the extra volume for the brembo calipers as they wear. HOWEVER, as long as you check your brake fluid once a year or so and top it off as needed then you can run the stock MC.

It's possible to run the stock MC completely dry though from never topping it off as the pads wear. A LOT of people just use the non-Brembo MC so I would consider it optional.