Modding: How much can you get away with?

[Yaris Revenge]

....WITHOUT voiding the warranty?

I still don't have a Yaris yet, but that doesn't keep me from daydreaming about the end of the year and all the toys I'd like to install once I get one. Off the top of my head, I'd like the NST pulley, lowered springs, 16x7 rims, maybe a short ram intake, and a cat-back exhaust later on. However, I won't touch any of it if it's going to screw with the warranty.

Anybody know what parts (if any) will void it?

Thanks,
~YR