i have had the tune up done on my car a year (20k) ago with BOSCH platinum 2. and today i changed all the ignition coils by myself...the question is, should i have replaced the BOSCH plugs with NGK or DENSO or should i drive another 30k and then replace them? and can BOSCH plugs make the coils go bad or harm anything else? is there any code that pops up when the spark plug goes bad such as SES or CEL etc. i will be going for NGK iridium once i get all the life out of my bosch plugs. btw its 01 max se,

 

u should stick with NGKs; on other japanese imports, especially the quad tips, they show bad symptoms in 15k miles use with starting and couple of misfires.
if you used the single tip platinums, i guess they should be fine, but since you're changing coils, mind as well change the plugs as well
as to them harming your coils, it shouldn't cuz i believe they have internal diodes

 

Some people say they can get away with it.. I wouldn't risk it, personally. Maximas seem to be picky about their plugs, and it might nip you in the butt later on. Be a shame, especially since you just replaced your coils - don't want them going bad in a year.