That looks good . I am going to upgrade the subs in my T soon but I tend to prefer infinate baffle loading , firing the sub through the fold down seats and using the boot as your box. this type of loading with a good speaker will give much better sound quality so long as the volume of the boot is more than 4 times the VAS of the driver and there is a reasonably good seal between the boot and cabin. In my home theatre I have 4 15" drivers mounted in the roof firing through air con grills into room, sounds awesome.