I just had a crash on Sunday race, this happen because I broke the steering wheel of my 3PK and had to retire from the race, but when I stop the car I got hit by another car sideways, my pipe flatten completed from both sides.
I know some has asked in the pass about how they can fix their pipes when something like I had happens.
I used the frozen system to straighten the pipe and it worked, but I had to do it four times to be able to get the pipe to normal volume again. I took a piece of cork shaped it to the size of the rear pipe hole and close all the other small holes of the pipes with putty, tie up the cork with a thin wire so the ice will not push the cork out and bingo, after four times in the freezer, every time I had to put new water to allow it to expanded at the max possible, this is because the expansion that the frozen water creates is smaller that the pipes was needing so by doing the process four times the expansion was bigger.
I hope this will help others that in the future could have this same problem