i put in a set of JJR coil packs, and when i pulled my standard ones out they appeared to be fine. However, within 5 minutes of having the JJR ones in the car died, and wouldnt restart. I changed the coils back over and it still wouldnt start. I found a blown fuse and changed it over, car ran and ran fine, and no fuses blew. Seeing as my standard coil packs seemed to be in perfect condition, my friend offered to buy the JJR's off me if i wasnt going to use them. As i packed them back into the box they came in, i noticed this weird piece of plastic hanging off one of the coils. On closer inspection i saw that one of the coils had actually "popped" and this plastic had oozed out of it and hardened, obviously the reason for the fuse blow. Since ive had the standard coils back in i have had NO problems, but i am yet to have time to return the JJR coils because ive been working 6 days a week.....also i should note that one of the JJR coil packs came WITHOUT a spring inside it, so i had to use one out of my original coils, however this was not the one that "popped"....thats my feedback hope it helps....