you took out your cat? damn! im about to get a high flow cat

 

don't bother with the high flow the neon cat flows pretty good and if go too free flowing with the exhaust you will loose power down low. Unless you go turbo then no backpreure= good

and if you want mod that gives both power and gas milage get a under drive pulley.

 

I see, so to conclude this... the srt4 back pipe (straight piped)wont hurt my engine? and I dont need the o2 sensor or new ECU at all?

 

no you are fine. technically since you still have a cat, that is providing enough back pressure, so you are not running a free flow exhaust. you will be fine

 

it's just a stock SRT4 back pipe I have on there. everything before the back pipe is stock.

 

Well right now since I changed too new plugs and wires with all my mods I now get 29 in the city and 35 highway so the srt exhaust has not hurt my gas mileage its helped out nicely especilly with a glasspack on her.

 

The srt exhaust will decrease your gas mileage due to flooring.

trust me.

 

yes your friend is correct you lose backpressure and will lose performance....BUT it wont hurt your motor or anything else and you will not need what he said....to keep your performance just install a glasspack muffler they are cheap and you can get it done at your local muffler shop...I would get a glasspack muffler if I were you.