Sheared bolt underneath

[leegt5]

Tried replacing the cat today and it was a complete pig, had to dremel off all the bolts holding the cat to the downpipe then wanted to remove the tunnel reinforcement. I went to undo the bolt to remove it and the bolt sheared off, my question is can I drill out the remaining stud and replace it or is it welded to the underbody ??

[*tell*]

yep happened to me a week ago 
all 4 have broken off and the tray is in the garage
at the mo. am going to a some point ask my
mate to weld 4x bolt to the floor so i can refit it.

[leegt5]

Looking on ETKA the part number for these welded bolts is

N 901 693 01

20p Each !!

[nelds]

replaced my exhaust today from cat back. i managed to shear 2 of mine also......i'm gonna just hope that the 2 hold it....  the middle section of heat shield fell off too, do i need to refit this..??.....the gap between the underbody and exhaust pipe is pretty big so i can't see it getting over hot. all the holes had rotted away and there's nothing to hold the shield on, any ideas how i can fix it back in place if i have to.......
also need to get it adjusted as the drivers seat is vibrating like hell on tick over

[leegt5]

I thought I'd try the remaining 2 today with my impact wrench after giving them a good soaking with WD40 and guess what !! They came undone a piece of pee without shearing off !!

Wish I'd used the impact wrench instead of a ratchet probably wouldn't have sheared the other 2...

Still never mind !!

Gonna get a couple new studs from volkswagen and weld them on !!