Danny,
For leather and vinyl I use Top of the lines "Deep Clean" and I dress the leather with 4Stars Leather Conditioner as it is the best I have found to date.
I hardly ever put any dressing on vinyl or in the vents as it only attracts more dust and looks....well cheap and fake, IMHO. If I do happen to use a dressing on the vinyl I choose the one put out by Klasse.
As for carpets, try the pre-spot cleaner made for fabrics and upholstery made by "303". You can get some from the Platinum website or Top of the Line's website. Spray some onto the area needing to be cleaned, let it dwell for a few minutes, scrub it and then spray the area down with clean water from a spray bottle. Use your wet dry vac as an extractor and a white 100% terry cloth towel to mop up any excess dampness.
Never over saturate the carpets, with either water or cleaner, especially cleaner as any left over cleaner will just attract more dirt faster.
Hope that helps,
Anthony