sub box help

I recently bought 2 10" rockford fosgate punch hx2's.  I put them in a double (divided of course) sub box, and they hit pretty nice.  However, as always, I'm looking for more output.  I am pretty good with building boxes, I have built 3 sealed so far and they all turned out quite nicely, however I have never tried a ported.  I want to go with a slot ported design, because I can run the ports along the divider and around the back if need be.  However, I need a little help with calculations.  The only 2 restrictions are that the box must be less the 31" wide and 13" high.  I am looking to tune around 35 hz.  Also, any good sites with slot port tutorials would be greatly appreciated as well.I drive a neon...got a problem with that??

Have you checked out this site before? http://www.diysubwoofers.org/portcal.htm Also this one has calculations etc. useful stuff and well presented as well. http://www.carstereo.com/help2/Articles.cfm?id=31