I just helped a friend of mine install a pair of subs in his car. They are cerwin vega steath 10's. My friend has the copy of the t/s parameters or i'd list them. The subs are installed in two seperate boxes. Each box is 1.65 ft^3 and are ported. They are tuned to 35 hz. It's not bad, but he feels it needs a little more bass, they are in his trunk. I was wondering if there is a way for me to improve the spl output without resorting to bandpass and also keeping the existing amp/speaker combination. I was thinking using a horn-loaded box. I have never built one of these though. I was looking into the DEC ware horn loaded bass box as an option. Any ideas? thanks.