ya, hrm. its was tricky. we attached the cat end first then one guy above the car pushing hard on the pipe then one under the car with
a ring spanner tightening it up 1/4 turn at a time. until it was tight enough that it was easier to do up.
we were considering hitting it with a few times with a flat edge piece of metal and a hammer, something like the end of a large'ish nail.
but we got it in so didnt need to.
this one thing too the longest to do.
luke a mech will be able to do it in 2 hours easy.
also image attached for more info.
because the pipe bends back in on its self in that spot there is very little room for the bolt to turn, let alone get a spanner or drive on there.
once we got it started it was easy.