Toyota/Lexus wants you to change your plugs at 8 years, even if you haven't reached the 120K miles spec, because there is a danger of the steel plug threads seizing in the aluminum head. Of course, you could just pull them, clean the threads, and re-install the used plugs if you run this risk.

I would buy and install a $15, used, OEM coil before putting in a new coil from a non-dealer parts supplier. I've done this on my Tundra, and even bought an extra, used, OEM coil to have on hand for either vehicle if needed in the future.

BTW...Napa sells kits for replacing the seals on OEM coils. I replaced all seals on my Tundra coils as some leaked moisture into the plug tubes.