Nice work man! Looking forward to seeing pics. I previously had a 4th order in my Buick with 4 SA 10's. I've switched to a ported box and I honestly like it better. Maybe your 4th order design is better than mine was. I blew 2 subs with my design
I'm currently in the market for the Hertz's as well. A local dealer will be giving me a price tomorrow. Send me a PM if you'd like me to get you a price.