unlike other posters who were born with knowledge, I too had to learn as I went along. And I also asked questions that some may have thought stupid, but weren't stupid to me since I did not know. Fortunately there were a few that took a few precious minutes of their important lives and helped me instead of ridiculing me.
To the OP; the cheapest, easiest, most bang for your buck horsepower gains will come from a cold air intake and a tune. Don't buy a cai that requires no tune, it won't help. JLT and C&L are probably 2 good places to look at for a cai. If you can get a package deal on a tuner with your cai that's the way to go. Download the tune for your intake and a higher octane rating and you'll pick up maybe 20 hp.
You can also raise your top speed limiter with a tuner. I'm hoping you're hitting 120 someplace that's safe, like a track so I won't assume otherwise.
Good luck with your quest for more hp and speed. It's what all of us car guys want. Working on your own car and making it different and better is a great hobby.