1. Can you replace a muffle without welding?
Bolting a muffler in place does not require welding equipment, but you still need the specialized expertise and abilities for the installation. To reach the undercarriage, jack up the automobile, check that the joints are securely fastened, and then carefully lower the car; you must be able to do so.
2. Which is better for repairing the exhaust pipe, clamping or welding?
A stronger connection than a clamp can offer, and one that will endure the whole life of the pipe, is provided by welding. The drawback of welding is that it requires specific knowledge and equipment. You will need expert help if you lack the necessary tools.