ecu

I'm planning to put on a new throttle body and a new exhaust system on my 5.0. I have heard that without a performance chip, my car may run worse. But I also know that this car is from 1991, so would these upgrades hurt my performance and make it slower or would I need to get a chip to make it...

Not able to find where it is. I'm planning to replace the chip with a performance one. Does anyone know where it is?