Anyone know where I need to cut?

 

Does it slide over or is t flush?
Are you doing the welding?
I would have got the part that has the curve in it. https://www.ebay.com/itm/11095794005...Bk9SR5D1v57mYw
OR
https://www.ebay.com/itm/19180716287...Bk9SR5D1v57mYw
OR
https://www.ebay.com/itm/23540296057...Bk9SR5L1v57mYw

I would hand the 2 parts to the welder, let them do the cutting.
BTW, the cracked pipe is usually the result of a bad motor mount.

 

Zzp support said either one would work. I figure the one without the bend would be easier since it's before the 02 sensor thread.

I didn't get the calipers out but the end felt the like same size as the downpipe.

So maybe cut it just after the thread?

And I would have just had someone weld the stock part back so save money, can't justify the $140 part 😪

 

You know there's not a whole lot of room for errors.

 

Has to be right.
Ideally a bit of overlap of the two pieces so there is plenty of material to weld.
The flex would take a small offset I'd think.
Bring all of it to the fab shop and let them deal with it unless you have the mig to diy.
Original could repaired and return the new part.

 

The metal on the flex is too thin to weld, blow out more likely.

 

Original is stainless steel and the ribs of the flex makes it hard to weld in the grooves, even with a TIG

 

What about on top inside? That's how the zzp part is

 

You can try and braze the existing flex pipe. It may hold well if you cover it well.

 

Even if ugly it should hold. This was the only place I see it broken. Just gotta tell the guy not to go on the flat part where it mounts lol