Heat Shield?

Hey, does anybody knw what effects it will have if you remove the heatshield of the 4 cyl? And is it practical to hollow out the pre-cat that comes right off the exhaust maniflod?

wouldn't do the pre-cat, u'll throw a ses light you can do the cat w/o throwing one though

you can hollow out the precats for a small gain but only if you move the o2 sensors that were after the front cats to behind the rear one. they have to read that the exhaust is getting broken down through a cat.

also, removing the heat shield will only make your car set fires if you drive across the grass.