Q8 GooGles

Hello.

I bought an '05 Mustang GT around a year ago and it had no cats + Flowmaster mufflers.

Where I live they are very strict about car modifications so I decided to just return the car back to stock.

I asked several people about this and mostly what I got was it's not recommended to put the cats back on a car where they were removed before because it will affect the car's performance. How right is this statement? And would you guys recommend I put the cats back on + stock mufflers or just get the stock mufflers?

Also, when I say "affect the car's performance" I mean it would drop to below what it was before when the car originally had the cats on.

Thank you

LilRoush

Someone was on crack and talking cars with you.

Putting them on won't be bad at all. And if they are getting tight in your area, it's best to have them on. As for the mufflers... that's up to you. Some like stock quiet, some want a little more rumble.

craig71springsport

Whoever you were talking to was a moron. All the cats are going to do is restrict exhaust flow and take some horsepower away, they cannot drop the performance below stock, when they were originally installed. The only thing I could possibly think that would cause a "problem" would be with sensors on your exhaust, if any. Depending on how many cats were on the car, if you put less than there were on it when it came stock there might be an error code that comes up, but it will not harm your stang.

You can find high flowing cats on any performance parts website. Just two of those will bring up performance nicely from stock flow. Plus if you keep the flowmasters on they will compensate for the possible loss in HP from the restrictions that cats would put on.

Q8 GooGles

Thanks for your answers guys

ryan1994mustang

yeah, what these guys ^^^ said. and i think the 05+ cars probably required a tune for no cats, so you might have to get the tune back to stock, but im not 100% on that