Last weekend I had a mechanic come over to change the fuel pump and transmission fluid for the RV. I also paid him an extra $70 to change the spark plugs. I was going to do it myself a few months ago but gave up when I saw there was very little clearance on 2 of the plugs. Took a spin on the freeway and noticed quite a difference. The olds ones were Berut and had over 50k miles. I used the Bosch plugs to replace them.