not that anyone cares but i just finished my ported box yesterday for my 15" type R.. first ported box ive made .. and all i can say is wow.. the frigin thing is so loud it like shakes my head(aimed the sub to the rear and the port is commin out behind drivers head .. i went with your advice glass and shrunk the box a lil bit to around 3 cu ft and tuned it a lil lower to around 33... sounds awesome though