To'o Paogofie

I need someone to help me find the exact speaker sizes in my 09 g37 sedan, right now I have a Bose system in it but wanted to replace the speakers and avoid going to the shops to find out and deal with the salesman’s pitch on what brand is better🤷🏽‍♂️. I have a brand that I love but don’t know the sizes I need (pretty sad) but it is what it is🤦🏽‍♂️Lol 🙏🏽Help🤙🏽