The PC-7 works without any clamps. It is like silly putty when you mix it and you can work it into the cracked area enough so it grips really well. Let it dry overnight if you end up using it. It will probably be stronger where you repaired it than the rest of your exhaust.

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1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles