mostly sound with the i/h/e combo, along with some psychological stuff. It really is hard to tell the diff. with a less than 10hp gain overall. Sure, it'll be a lot more fun to drive - but that's about it . You'll need to do something a little more serious to start getting a good feel out of everything. Don't get me wrong thouhg, and i/h/e car will still feel and sound a lot faster than a stocker, and be more fun for the driver to drive.

- Nathan