98 Civic DX

What type of modifications can be done to increase horsepower on my car (beyond swapping engines). Does anyone have any suggestions along with
approximate cost and potential hp gains. Thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.