The Helicoil will also return it to a M6 thread as well if you are not aware.
Just a heads up, the helicoil worked! I stripped these threads because I thought the exhaust pipe joint should touch the block. I suddenly realised this and wow, I was annoyed with myself.
Now with the helicoils, the exhaust pipes fit nicely on the block and I haven't had any problems so far.
I'll update if the helicoils loosen when riding the bike for a bit.
Thanks everyone!