I currently have intake, intercooler, downpipe and exhaust for my car. I'm about to change my spark plugs and wires and I was wondering if I should keep the 7 for leading and 9 for trailing for my car or should I go with something cooler. I don't know how to determine what kind of heat range I should be using and I couldn't find anything in the archive. Thanks for info.

 

Run BUR9EQ or BUR9EQP in all four holes.