I have an 02 SE. I am under the impression that my car should be chipped out at 128 for a max speed but the best I can get out of it is 107 before it shuts down. What are others experience?

your SE will be limited at 108 the SSEi'* are 128

You will need an aftermarket PCM to get rid of your speed limiter.

How will a new PCM affect fuel milage, what would the cost be and what will it do to my extended warranty?

I've used both the Intense and DHP PCM'* in my car, and my milage didn't really get affected by either, even though they are quite different from each other.

You can get an Intense unit for 100 bucks. DHP is over 200, but they are pretty much geared toward W-bodies (GP, Impala, Monte, Regal).

As for your warranty, it could void it, but for the most part, the dealers don't really know if you would have an aftermarket PCM unless they had to work on it, in which case, they would reflash it if there was a problem and you would lose the aftermarket code.

It'* your call if you want to do this or not.

SEs have 108 mph speed limiters due to teh * speed rating tires that are factory equipped, the SLE and SSEi have H rated tires, and therefore have a 128mph limiter