Best way to start?

[Beyond]

Hi all.. first time posting here, I've got a 5spd 2004 xB that's got the same 1.5L engine as the Yaris and finally I'm looking into bumping up the performance a notch. I live in a mountainous area so any added power in 2nd gear would really be appreciated.

CAI , 1ZZ-FE Throttle Body swap, Header, Exhaust... which one should I start first?

Any combos of parts that work particularly well together?

It's a newbie question for sure, but I'd hope those of you who has gone down the performance route and tried different product combo can recommend your preference, and of couse any personal nuggets of wisdom.

Thanks in advance