From a spacer nothing unless you are going to port it for n2o. Adding a CAI such as a Vararam would help with your get up and go and maybe improve the throttle response a little. However for the best improvement on throttle response you are going to want an 87mm ported throttle body, we can get one of these out to you for $379.99, and if you pair it with a tuner (currently Bully Dog 40430 is available for 2013's, and Diablo Sport is approximating 30 days out on their tune) we can work an even sweeter deal for you, or if you wanted to pair an 87mm TB and a Vararam we could get you a wicked deal too.
Just need the TB that is ok to email us at email@example.com
and we will get you special Z pricing.