Can having no exhaust or catalytic converter on my car affect it's performance or is loudness the only downfall?
Yes, having no exhaust or catalytic converter in your car affects the car's performance or the horse power. The gas mileage, engine operations temperature, fuel options and the exhaust sound are also affected in the car.
Yes, the performance will be greatly affected. by having no exhaust, your engine will Lose compression thus making your car in turn, slower and working the engine twice fold.