get a front upper strut bar..and a lower front tie bar. you can also upgrade your suspension bushings to aftermarket polyurethane bushings. other than that, you can get a carbon fiber hood to lessen the weight of the front end a little. if you want to go all out, you can get a chassis brace (i think thats what they are called) and rear upper and lower tie bars. if you did all that, you'd be handiling way better than a stock si.