Would a dual exhaust be good on my 01 em2 if I have headers and a intake system on it would I feel more horsepower or will it do bad for my engine

 

Are you serious with this request? Or is this an attempt at trolling? Not trying to be rude, but its hard to take your question seriously.

If you are being serious, you'll want to look at how many 4-cylinder applications out there have dual exhaust. There are almost none out there for a reason. It'd be strictly an aesthetic addition (if not a slight decrease in power for the extra piping and an increase in weight, which would make the car feel more sluggish). Also, you only have one header... so you don't need the plural form of the word.

Since you don't seem like you've actually read much in to the FAQ's, let me point out something for you. Traditional bolt-on parts add little to no power gains for the D17 (as a whole). If you want to see actual power gains, you're going to have to invest in either a stage 1 cam (with K-pro and an adjustable cam gear), a Nitrous Oxide system, or a turbo kit. You're not going to see anything without spending a lot of money on the D17. This is why most people just save up and swap it for a K-series drivetrain.