Hopefully they are not as had to install as the LS1 plugs. Remember have to lay on the ground and come from underneath with three elbows on your ratchet just to get number 8. Of course those big ol' headers didn't help.
I put the wires on and they are great! Didn't have to much problem replacing the number 8, still a pain on LS motors!!! I did figure out a trick, turn your wheel all the way to the left and this will allow enough room to reach through the wheel well and remove 8 and 6 plugs.
I am surprised how much better the hummer is running, I feel a little better response on the throttle and minor power gain. Every little helps! Recommended addition!