My 2014 Volt recently rolled over 100k. After reading many posts of gen 1 volts either getting major battery section failure around 80-120k or clocking over 250k without any problems and just basic maintenance, I checked battery cells state in special app several times and have decided to keep it and run it longer. Especially with todays car market(event thought I were recently offered couple grands more than what I paid for it in 2017). Anyway doing lots of maintenance today, oil change, drive unit(planetary gear-set tranny)fluid change, cabin filter,(engine air filter looks practically new, I think I changed it around 75k). Anyway my last item was spark plugs change. Everything oil related went smooth, all bolt took almost no effort, but as always-last item on the list can go sideways and can make you car disabled for couple of days. The way coil pack rail sits on this engine, you can grab it only from one side to start pulling. As I can see on volt specific forums now, outcome is very common. It was very snug there, I had to wiggle it and pull really hard. As a result contact spring tube snapped off on cylinder #1. Boots sat in valve cover also very tightly, and at that point I did not care much, so half of them got torn while I pulled them out with pliers. Cylinder #2 had something leaked into spark plug well and it was especially hard to pull out boot from there. While all other wells are sparkling shiny inside, that one has some white rough varnish and spark plug itself got corrosion on it. Spark plug electrodes look like they could of go another 50k easily(car had probably less than 50% on engine running in all those miles, 117 lifetime mpg as on now). Those plugs have laser iridium NGK part number on them and say made in Japan. New plugs that went in are also ACDELCO, but just say made in Taiwan. Amazon messed up big time delivering NGK plugs with same part number as OE 2 times already. For whatever reason they shipped all 4 in separate envelopes, and they came at different days. 4th envelope was not sealed all the way, so it had a small hole and it fell out. Contacted them, replacement envelope came 2-3 days later. Now it had small crushed spark plug box and cardboard ring inside, with no spark plug… contacted again and second replacement is still have not shipped out… so after couple of days waiting for order to be fulfilled, I pulled a plug (pun intended) and ordered from rockauto, even with one day of ground shipments delay it came pretty fast…additionally there is $3 rebate per plug on acdelco brand. Just ordered exact same Delphi coil pack rail from them and 4 NGK boots with springs, as it does not look like those coil packs come with springs(not pictured, not in the description).