Ricardo in my opinion stick with what you are using, in Colorado the temps are not really two high ,perhaps
couple of months of the year,your plugs are the correct colour, and you only do short runs. .
With Bosch the WR8DC is getting abit high,but no problem there where you live.
Also with NGK,alot of owners dont realize that there heat range is the opposite,the lower the number
the hotter the plug,the higher the number the colder.
Even though plug makers can cross reference say particular plug for a particular car ,
this is not always as acurate as it seems, like years ago i owned many Alfa Romeos, from
late sixtys to early seventies, with spica fuel injection,and some alfa owners used NGK,but wrong heat
range, and got caught out, most used Champion spark plugs ,and i did as well,just happened that they where the
most reliable with that model car.--regards.
