I also had an '07 Titan and I'd say take that truck to a pro. I like to do most of my own stuff because nobody cares as much as you do about your things...but that interior was a major PIA. I tried lots and lots of cleaners, whatever those seats are made of they are nearly impossible to clean. I just started getting the interior done whenever they'd have a detail special at the car wash.
I've had good luck using a rug doctor steam machine with the upholstery tool. Zep makes a carpet cleaner in an aerosol can that works wonders on the stains themselves, but the steam machine freshens and cleans all the rest.
