Removing your cat will not hurt your engine.. The engine management system trying to make up for the reading the cat O2 sensor is getting will make the "check engine" light come on. I saw somewhere that there was a fix for that so you could run with no cat and not have the check engine light on. If anybody knows let me know.
And as far as horsepower it is definatly a plus++++
I wouldnt expect more that 6-8 wheel horsepower. But for the price you can't go wrong. If you think you can get away with it i say go for it!
