can you run colder pulgs all the time or do you have to change them everytime your not running boost whats the long term on just running cold plugs.
You don't have to change them. Hotter plugs clean themselves better, and I think are better for emissions. If you go one heat range colder you won't experience any problems. If you were to jump say 4 heat ranges you might have some issues with the plugs not cleaning themselves well and fouling easily. Sometimes too hot of a plug can also cause preignition(usually on air cooled engines, not liquid cooled).
For example on my buell the cylinder head temp gets as hot as about 450 deg F, and with the stock plugs when it would get that hot(sitting in traffic, etc.) it would sometimes preignite. The plug retains so much heat that it gets so hot where it causes the compressed air/fuel to combust before the plug actually fires. I changed to the same plugs one heat range colder and it stopped doing that.
This usually doesn't happen with liquid cooled engines since the temperature is maintained better within a certain range, the plug doesn't get extremely hot like that and cause a hot spot for ignition.
A colder plug simply has less insulation around it's core(so it can transfer heat faster away through it's body and into the cylinder head).