I have never put MM oil in my 2004 crossfire, but i have used it in my 2000 oldsmobile alero. it was a fuel infected V6, and i did notice better performance and MPG. Like you though ive put it in every carborated car i have owned. Also it is good as an oil additive in the older cars. I had an engine sit for 5 years, and it locked up. i poured MM oil into the engine and down through the heads, 2 hours later i was able to turn the block by hand, and eventually got it to start. I dont know what is in that bottle, but I always have one close.