I just purchased a FI Q15 for a sealed application in a 95 Lexus SC coupe. I'll be using the 'spare tire' location for the box and should be able to get at least 2.25 cubic feet of volume. The sub will be driven by a JL Audio HD750/1. This car is basically a show car with big power and I wanted to add some finishing touches to the sound system and I think the FI Q15 will give me what I want ( more sound quality than SPL ). Currently I have a Pioneer AVIC Z110BT headunit, JL Audio ZR650 components in the front, JL Audio C5 6.5 coax's in the back deck being driven by a JL Audio HD600/4. The FI Q15 will be replacing a JL Audio 10W7 that is in a custom box on the left side of the trunk. Looking forward to the build and sound.