I usually use ordinary spark plugs (single tip) or the Autolite platinum spark plugs (single tip) and changing my car's plugs every 25,000 miles. Normally, my Ford Escort makes around 30 miles per gallon. When my Ford reached 100,000 miles, I bought these Bosch Platinum 2 Spark plugs (double tip) thinking it would run better and will make 30 + more miles per gallon. My car run better but my car was only making between 20 to 25 miles per gallon. I drive 100 miles a day and I am getting broke using these Bosch plugs. So around 2000 miles of usage, I changed my spark plugs again to single tip Autolite platinum spark plugs. My car went back to 30 miles per gallon. I love it. Using single tip spark plugs, you can adjust the gap clearance on the tip while the Bosch Platinum 2, you cannot adjust it at all.
Now the bad part:.... When I bought these Bosch Platinum 2 Spark plugs, on the back of the packing case it is written: If not satisfied with the performance, return the Spark Plugs with the original receipt, write my name and address on the included slip and mail it to an address in Phoenix, Arizona and I will get a refund of my purchase price. Which I did and even wrote a letter why I am not satisfied. I spend $3 postage with delivery confirmation number just to get my $18 back. My parcel went to Arizona but the company moved already and was forwarded to El Paso, Texas. US Postal Service website shows my parcel was delivered to Texas. That is the last time I heard of my parcel 8 weeks ago. Did I get any refund? NO!!!!! NO!!!! NO!!!! Bosch Company promises 4 to 6 weeks to get a refund. NEVER GOT IT. I do not have proof anymore because they asked for the original receipt and all my spark plugs.
Suggestion: If your car originally comes with a single tip spark plug, use the same.