zachary1988

I have an 04 GT and would.like to change out my exhaust system starting with headers. My first Mustang and do not have any ideas. I was thinking about the American Thunder Flomaster. Not sure about what headers and crosspipe. Thanks in advance. Ed.

xx10Gt

lots of questions need to be answered.. budget? do you want an x or h pipe? cats or no cats? If you choose no cats you will get a check engine light which will cause you problems if youre in a state that does obd for inspection. What kind of headers, longtube/shortube?

zachary1988

I do have a budget but I want to do it right. I do want to do the Flowmaster 40 series. I am not sure about which headers, long or short. BBK is a good set of headers that I was told. I heard that cross is better than the H pipe. This what I know so far. Thanks, Ed.

Soldier GT

My experience:


I run the 40's along with Flowtech LT's (thxs Rob). When I 1st bought my car I asked the same question (which was best shorties or Longtubes). Overwhelming consensus was that the LT's were much better because the shorties will not yield you any power. Being hard headed I bought the shorties and for the price of the install it was a complete waste of money. Maybe 2-3 rwhp, about as much as a CAI system.

One bit of advice I did take was with the mid pipe (X or H). If you're going with the flowmaster exhuast kit I would highly reccommend buying the H-pipe. Being that the flowmasters are a chambered exhuast system the H pipe would give your car more of a old school muscular sound. Now if you're one of those guys who would prefer a little louder sound with an occasional popping sound then go with the X.

I would guess the two maijor drawbacks of flows would be the drone sound and also the possibility that the muffler could rust out quicker than other brands like magnaflow or borla. Reason being, flowmaster mufflrs are aluminum while the magnaflows are stainless steel.

zachary1988

I forgot to mention that I will go with the cat back since in Illinois, we have to do the air inspection. I thought the Flowmaster has the stainless system. I am going with the sound more than the hp since I am not going to do much more else. Thanks, Ed.

VTX1800N1

If you want perfect sound, you need to look at Borla.

Sent from my XT1080 using IB AutoGroup

Soldier GT

If you're worried about EPA inspections, the LT's are most def out of the question. I would look at buying a really good catback system and like my man VTX said , would be a good way to go. It'll cost about 600-700 bucks but it'll be well worth it. If you decide to buy the flows and shorties you're looking at about a Grand to 1100 bucks (parts and labor).

zachary1988

Why would the long tube headers cause issues with the inspection? So the Borla is the better exhaust even if the Flowmaster is stainless set? And the cost of $1100 or about is fair enough. Thanks, Ed.

Gt04

If they do a visual inspection long tubes won't pass because they aren't legal in emission counties and states. Hence why most websites state "for off-road use only". Keep your stock headers and just get a cat back and possibly a high flow catted mid pipe and call it a day if you have to worry about an inspection. Could end up saving you money in the long run...... if its just for sound and not performance long tubes aren't worth the money and hassle anyways.....

zachary1988

Thanks for the info. I did not know that about LT headers "for off-road use only". I will keep that in mind.