Yeah I've got torx bits already, CMP sensor is fairly hard up on the firewall hence I couldnt see the bolt heads (which is why I had assumed they were allen heads this morning). Shouldn't have any problems getting it undone once I try again with the proper bits.
Was using a breaker bar already for the cylinder head bolts but once they start to round I've found it usually just gets worse as you are pulling from one side, hence why I went to the impact wrench to try that instead. I had actually gone out earlier this arvo looking for those sockets you mention but nowhere within cooey of me stocks them which is why I came home with the impact socket instead to try. Will have to order some online.
Impact socket is a good fit and seems to be holding so I'm hopeful that will do the trick.
UPDATE: CMP sensor removed, amazing what the right tool can do

Cracked 6 of the 8 bolts on the RH bank but the last two are being difficult. Picking up a 1250nm chicago pnuematic impact wrench in the morning, if that won't do it then I'll cut my losses and burn the POS
