Tools and equipment needed:
1. 14mm socket wrench
2. Dishwashing fluid
3. A friend to help you (optional)
4. Car ramps or jack stands (DO NOT USE FACTORY CAR JACKS TO SUPPORT THE CAR WHILE YOU'RE UNDER THE CAR!!!)
The stock Celica muffler is held (connected to the car) in 4 places. 3 are from rubber hanging posts and 1 from a connection to the rest of the exhast system.
You will need to use a ramp or jack stands to raise the back of the Celica. Please don't use the factory tire jacks to suport the car. They are weak and the car may fall on top of you.
Unbolt the muffler where the muffler connects to the rest of the exhast system by using a 14mm wrench. You will have to remove 2 bolts. The area can be seen just in front of the rear passenger side wheel.
While you are under the car, squirt or rub a small amount of dish washing fluid on the 3 rubber hanging posts. You need to do this to be able to slide the hanging posts out of the rubber holes. This is where your friend can help you pull and take the muffler off. Make sure your car is properly raised. While taking the muffler off, the car will shake a bit and may cause personal injury if it falls on you.
To install the new muffler, just reverse the procedure. Don't forget to use dish washing soap to help you get the posts back into the holes.