In changing my plugs and despite being super careful, I did what I fear most...stripped a spark plug hole...it's been years since I changed them, and I can't remember if I had a problem in the past because the previous owner started a cross...the plug is holding for now, so I'm not messing with it. Given all the aluminum heads on our early MBs, has this happened to others, and if so, what did you do short of pulling the head? I've heard there is a better choice than Helicoil...appreciate any input...thanks...