Replacing Twice Pipes with Original Stock Exhaust in a 1972 Datsun 240z

My 1972 240z was previously modified with this twice pipe exhaust system which is loud as hell:

Motorsport! Twice Pipes Exhaust (For 3-2 Headers), 70-78 240Z-260Z-280Z - The Z Store! Nissan-Datsun 240Z-260Z-280Z-280ZX-300ZX(Z31/Z32)-350Z-370Z Parts

I want to go back to stock so i can use my car as a daily driver and not a racing machine. Just as a normal sedan. Is this what i need to purchase and have installed:

Motorsport! MSA Premium Exhaust System, 70-8/74 240Z-260Z (for 6-1 Headers) - The Z Store! Nissan-Datsun 240Z-260Z-280Z-280ZX-300ZX(Z31/Z32)-350Z-370Z Parts

or i will only have to buy the exhaust muffler???

Motorsport! Performance Stainless Steel Muffler - The Z Store! Nissan-Datsun 240Z-260Z-280Z-280ZX-300ZX(Z31/Z32)-350Z-370Z Parts

Can someone please guide me on what i really need?