SS_Firehawk

1. No, it will not hurt the vehicle.
2.No, a tune will not be required. A tune will be required for all three mods you are looking into if they are all installed.
3.Shortie headers might net 5whp over stock, most of the gains are seen replacing the catalytic converter and exhaust. Stick with stock or go the full long tube headers. The only thing the Stillen header has over the stock header is weight and a better merge collector.
4.The Y pipe and muffler on the stock exhaust it restrictive and gains usually measure about 15whp-20whp. The headers or cats you install will have a dramatic impact on the sound of the exhaust, stock or aftermarket. Use the exhaust threads figure out the sound you want.

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