aem makes a CAI for the '03 4cyl. modacar.com sales them for
$185. dc sports make an aftermarket exhaust (TCS exhaust) for
$659 @ modacar. there are also aftermarket springs from h&r and eibach also @ modacar. i have not seen any aftermarket shocks or a big brake kit for the '03 models yet. i will keep on the lookout.
