aftermarket exhaust systems

i have a 1999 durango SLT 5.2L. besides the sound, i was wondering if a new exhaust system will really increase my gas milage noticably, and will it decrease the value of the car by putting new exhaust on it? does putting it on make it unsafe for the vehicle? ive heard that car makers make factory exhaust for a reason. and if anyone can recommend some brands. ive been looking at gibson stuff it looks good, but correct me if im wrong.

I basically have the same question only it's for my 99 Durango, so if you find out please let me know. [email protected]

I have a Flowmaster muffler with a 5.9L engine, and boy does it sound good. It does not make the car unsafe in any way, and I haven't noticed a change in the gas mileage. I don't know if it affects the value of the car or not, but I don't think it would change it much, it just depends on the buyer.

I have a flowmaster force 2 cat back on my 4.7 durango. I noticed a nice increase in mileage but I also had intake done first so I'm afraid I don't know exactly what the exhaust would do on it's own. It could increase the value with certain people or it could reduce, depends on whether the buyer likes it or not.