I dont have my book with me, but I dont think plugs are technically due until 30k or something like that. But being that the car is almost 4 years old, I'd probably do alot of the things based on time rather then mileage.
Personally, I drive mine hard and so I did plugs at 10k, changed to what I heard was a better plug. Im at about 12k also, getting ready to change brake fluid, clutch fluid and rear end gear oil. And do a change of tranny fluid, about 3-4 qts comes out. So its just minor stuff, but gives me piece of mind. You might change your airfilters too, either just stock replacements, or upgrade to a better filter like the green filters.
If you follow the book, it will give you time or mileage guidelines, and people will always debate about that. I do things earlier then the factory recomends on my sports cars or sports bikes. They get alot of hard miles and track time. But on my daily drivers and our SUV, I follow the book.