if you have every hauled you hood and trunk around you'll notice. its been proven time after time that weight reduction will easily take simple bolt-ons. look at SCCA, the mods rarely go into engine (except for upper class i.e. GT1) and most cars run quite fast. i would go with weight reduction if i where modifing my car (its my daily) but dont be stupid about it and have 5 subs with 3 amps in your trunk then take out your spare tire.