Yes u need the valve springs because you are able to rev to 9100 which is a rpm range vunerable to valve float. The ecu is an awesome up grade if you are going to run fairly stock. Throw mugen headers and cat-back and their air box, and that is how it is made to be run. If you want to do internals, you are better off with like the hondata or aem plug and play. The mugen way is a fun reliable way that you don't have to worry about the problems of supper tunning, and is a good increase in horsepower. Lots of people think it is to expensive though. It is up to you. :? Hope this helps.