13. Emissions Removal
It is no secret that a car will run better if the exhaust system is free of all catalytic converters and mufflers that can choke the engine. However, in the quest to meet safety regulations, manufacturers install multiple exhaust monitoring sensors, mufflers, and components to pass emissions tests. However, in recent years, most manufacturers are able to produce fast and powerful yet still environmentally-acceptable sports cars.

But some people remove their mufflers to “free” the engine. But by doing that, they mess with the engine’s electronics and ruin any warranties they have. Also, they’ll have big problems with the law since they clearly forbid cars with emissions equipment missing.