A) find a torex screwdriver bit that goes in real tight. Tap in with a hammer if that is not too hard on the muffler. Use whatever size wrench matches the hex on the bit.
head strips again?
B) Try a 90° drill attachment and use a left handed drill bit. Drill in reverse. You might loosen it even if you cant get on it straight.
bit cuts but not loosens?
C) Dremmel cutting wheel. Cut a slot. Taper one edge of a 1/16" strap of steel. Use as a screwdriver.
Slot strips?
C) Use dremel to grind whole head off. You can use the flexshaft attachment and get in there to grind the remaining threads that will prevent the baffle from being pulled out. OR go back to the 90° drill attachment.
I suppose a soldering iron would work also.
Maybe for tiny screws. M5 is probably going to be too big for a soldering iron. Couldn't hurt to try though.
Deep Creep would also be worth a try.
I once removed a bolt with busted off head. Find/grind a flat spot. Place a scribbing tool on the flat spot and tap counterclockwise with a hammer. It's very tedious but this will work.
* Last updated by: Rook on 5/13/2018 @ 4:18 PM *
'08 MIDNIGHT SAPPHIRE BLUE Now Deceased