Technically tips wouldn't do anything at all. A new muffler would change the sound but you wouldn't notice any HP gains. New headers and a high-flow cat would actually help get you what you were asking for.
Sadly I don't think the naturally aspirated motor is set up to make much power. So you might be looking at ways to utilize the stock horsepower better. Springs, struts, weight reduction. You might think about some lightweight pulleys though. They're not too expensive and fairly straightforward to install.
But welcome to NASIOC