i had the bosch platinum 4's for about 6 months, and i had no problems with them, but i have also heard that they can mess things up further down the road so i switched to NGK iridium, as far as im concerned the bosch are fine, but just to be safe go with NGK
a crazy thought that ive always told people.....spark plugs will NOT make that big of a difference for about 98% of you (and even then, not that big of a difference)....and there is no reason to pay $20+ for plugs....pay <$10 for coppers and you wont know the difference (aside from the extra money you have in your pocket)
ngk iridiums are about 12 a piece and the copper ones are cheap v power plugs are 3 dollers each i like the iridiums the best longevity wise ,copper plugs dont last as long copper plugs last 30k while iridiums last 80-100 k