Which one do you guys perfer?
I have been using 9s all the way and i just switched to 9/7 stock set up.. I really cant tell much of differences.

car is running rich and i would like to lean it out a bit..
what ya running on ur modded 7?

 

i rather run a little rich than lean in any way...

lean=bye bye motor

 

it's the heat range. depending on mods/boost people will run a colder plug. meaning it retains less heat so is less likely to be a "hot spot" and cause pre-ignition. that said they will foul faster during calm driving because they will not get to their self cleaning temp when you are putting around. everything is a compromise

 

You won't get leaner by changing your plugs.

 

thinking about getting msd ignition or hks twinpowe.r

 

anything else done to the car?

 

all the bolt ons except turbo upgrade.