Nero makes the interior, excluding the leather, look exactly like it did the day I picked it up from the dealership. I figure if I start using high quality products now, 4500 miles, then when I hit 50K miles the interior should look just as good as it does now.
As for the leather I just bought some Wolfgangs leather cleaner and conditioner, I found this on the LGT forums as well, and it should arrive tomorrow. If it works better then the Maguires that I used in the R/T I will make another post. I used the Maguires on the seats of my moms Maxima a few years back and didn't like the results, but it always looked great in the R/T. Unfortuantely the seats in the LGT are more like those in the Maxima then the R/T so I knew that the Maguires was out.