Most of the interior is vinyl or plastic. The dash in the MY04 has is a nice simulated leather, but it is just vinyl. For MY04 (what I have), you have leather uppers on the seats, leather on the sides of the center console, leather shift boot & knob wrap, leather wrapped steering wheel, and a bullet shaped patch of leather on the mid-section of the door. Everything else is vinyl or plastic. I believe MY00-MY03 are pretty much the same except for the center console.
For maintaining my cars, I've always been a Meguiars fan so...
For the all interior vinyl & plastics I use
Meguiars Gold Class Vinyl/Rubber Protectant. This stuff is good, but don't spray it directly onto any part of the car. I find it works best by spraying it heavyly onto a clean terri cloth and work it into the dash & plastic until it is even looking. Then with a second clean dry cloth, work on any parts that still look wet. It gives a nice deep black finish that is not shiny or slippery when done.
For all leather I use
Meguiars Gold Class Leather Cleaner & Conditioner. Similar to the other, heavy on the conditioner, but make sure you rotate the cloth sections (fold in 1/4ths). You'll be surprised how quickly the rag gets dirty from the oil, sweat, salt & dust that gets embeded in the car with frequent top down use. I recommend at least 2 full passes of rubbing in the conditioner to make sure you get the grime out before doing the clean cloth rubout.
Of course, that's just what I use, I'm sure there are plenty of other people out there who have their own opinions...