I have Bosch Platinum +4 installed in my 1989 325i. They are in there for over 31K miles so far and engine runs great, gets good gas mileage and performance. When the time comes to replace them I'll go with them again. Prior to these plugs I always stuck with the factory OE plugs. The engine is stock except for JC chip. I installed them on the recommendation of another club member because he liked them on his 325i so when the time came I gave them a try.