What I would suggest for the best integration is getting UMIK-1 measurement microphone and then using MSO (multi sub optimiser) which has helped me loads to integrate 4 subs perfectly and give a flat response across every seat.
That way you can be 100% sure what you’ll be getting and that your response is exactly what you want it to be.
There are many videos on YouTube to help you out. And I would be happy to help out as well if needed :)