Not much is available for the new 7th Gen. Accords. If your looking into getting an aftermarket exhaust system then you may want to checkout DC Sports & Apexi since they both have an aftermarket exhaust system available for the inline 4 i-VTEC 03' Accords.

As for lowering springs you have several choices available from Eibach and H&R. I'm not sure if Neuspeed has a set of lowering springs for the inline 4 03' Accords. Only coilover available is by Ground-Control however Ground-Control is not a true coilover setup. It's just a sleeve coilover that requires aftermarket shocks/struts.

There are no aftermarket shocks/struts available. Both AEM & Injen have cold air intakes.

Comptech is supposedly working on several products for the 03' Accords but mainly for the V6 Accords. Greddy is also working on an aftermarket full cat-back exhaust system and is probably for the V6 Accords again. You may have to go w/ a custom exhaust system for your inline 4.