I just did this also. The plug I got from Amazon so it's around $11 each. Getting the coils and plugs out of all 8 were pretty easy. I had a hard time pushing the #4 and #8 coil back in though. That last 2 mm lock that create the suction for the coil was a nightmare for these two coils. Turned a 1.5 hrs job into a 4 hrs battle.
Finally figured out to use a long metal bar as leverage so I can push the coils straight. Other than that, relatively easy. Should be able to cut it down to 1.5 hrs next time. Thank you for the forum members for all the info and detail DIY on this.