I worked for the nations #1 Bosch dealer for a while, and I NEVER recommended +4's because the exposed spark kernel is bad in high compression and/or forced induction engines. The Bosch Platinum's are great for cars with plug fouling problems, though. I use them in my motorcycle and Valiant.
I put them in my SL last spring. No problems, but I have since read more on this board and will probably put in NGKs with my next tune. I'm just too lazy, cheap, and it's getting too darn cold to go remove the plenum again!
Bosch makes the +4's in a version that they list for the VR4, they just don't work. So its not a case of putting a plug in that was not intended for the car by the plug manufacturer, it is a case of the plugs not working in the car.
Wow, I never realized so many have had problems with these plugs. I live by Bosch +4 and have been using them for the past two tune ups, but I have a Base model. It hasn't given me problems but I definately will not use them on my future VR4.
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