I have a D145 JBL 15" speaker that was re-coned with an "E" kit. I guess it's now considered an E 145. I am thinking about going to a lighter speaker such as the Eminance Delta Lite Series. I like the tone and the differance in weight is almost 20 lbs. less. The Eminence is also rated at 300 watts. The cabinet is homemade, I got the plans from the JBL web site. http://www.jblpro.com/pub/manuals/enclgde.pdf I went with the number 6 cabinet design. Can I simply swap out the speaker for the Eminence? I don't know anything about the Thiele-Small Parameters, maybe someone here can advise me. Here are the Eminence and JBL specs. http://editweb.iglou.com/eminence/eminence/pages/products02/neo/neo2515.htm http://www.jblpro.com/pub/components/eseries.pdf Thanks for any help.