Milos,
You shouldn't have to remove the headers. The first and last plugs on each side are tough to get at, but you should be able to do it with a box end wrench. That's how I get at mine on my ZZ4. Ya can't torque them in but You should be able to tighten them by "feel." Or torque the middle ones, and get a feel of how tight they are with a box end, then do the others. Just a suggestion, but easier than taking off the headers.........Don B
You shouldn't have to remove the headers. The first and last plugs on each side are tough to get at, but you should be able to do it with a box end wrench. That's how I get at mine on my ZZ4. Ya can't torque them in but You should be able to tighten them by "feel." Or torque the middle ones, and get a feel of how tight they are with a box end, then do the others. Just a suggestion, but easier than taking off the headers.........Don B