Wal-Mart sells a line of cars in the toy section called "Muscle Machines" which are 1/64th size cars. They have a section for "Import Tuner" cars (Honda Civics, Toyota Supras, Ford Focus etc). Anyways most all the Import Tuner cars has a shiny chrome plastic muffler, which comes off very easily. And can be easily attached to ANY ZZ or Microsizer. The result is awesome :-D
I couldn't find a picture of the back (I have a digi cam, and most likely will take a pic later on).
Well thats my helpful tip of the day, if anyone knows ANOTHER cheap source do let me know

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Price Tag of Car at Wal Mart: $2.48
PS : You can also use the body of the Import Tuner cars on your Zip Zaps. Slight dremeling is required around the tire area and it "should" fit. I don't have a Dremel tool, but I plan to get one one soon and try it out

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