Stupid question, but what do they do except start the car?

 

You were perhaps thinking of using a different brand of spark plugs?

One word: "Don't".

 

Not really, but I saw someone listing them in their sig, so I thought maybe they do help performance.

 

They don't just start the car. They fire for each and every combustion, otherwise, there would be no combustion. Use the NGK BUR7EQ and/or BUR9EQs. Other brands most likely will not hold up to the heat, will crack, and drop pieces of them in your engine, basically ******* it up real bad.

 

Ok thanks! I have new plugs waiting for me, but I'm gonna change them when I do the ATF trick.