I have read a thousand differant opinions on this question, but I'm still am undecided. I have a 1999 F-150 4.6L with 93,000 miles. I have to replace the exhaust. I want a stainless system, SI/DO the rear. Will one of the systems give me a better performance (that I will notice) than the other. I want it to sound nice but don't want to much drone. From what I'm reading Flowmaster 40 is louder but no difference in performance, Magnaflow is not as loud but will notice a difference in performance. I also have an aftermarket Hidden Hitch will it fit around this?

 

If you don't want it loud with drone, you will most likely be happiest with the Magnaflow. I have heard that the Flowmaster's are quite loud and appeal more to those who like it loud. Can't help you on the dual rear exit though, as I deliberately avoided that because of the problems with connectors and going around the hitch. I have DIDO behind the passenger rear wheel exit. I converted from SI to DI by just using the Harley edition Magnaflow and getting rid of the y-pipe. I am very happy with the system.

 

I had the 4.6 with Magnaflow cat back and it is a very nice system. I had flows on the car first and cut them out, that was a waste of money I only had them on for 2 months.

 

i love my flowmaster, flip a coin and go with that decision making process, you are going to get all the same anwsers as before with no factual dyno sheets to prove any gains and the difrences, it is a tose up between the two, so flip a coin

 

Since you mention you want a stainless system with no drone go with Magnaflow. You probably won't be able to "feel" the difference in performance between the two.

 

Can a muffler shop weld stainless so it won't rust? Am I better installing it with stainless straps

 

I kind of in the same situation with my truck its a 2000 with 95000 on it also a 4.6 not sure witch sytem to go with or just leave it stock until next summer and just trade the thing off for a new truck.

 

If you want a good true V8 muscle sound outside of the car, flowmaster is the only way to go. As for performance, you aren't going to get 30 HP from either of them, or probably not even 3 for that matter. The issue of exhaust is one that can be taken many different directions. You may not benefit from say, a dual 3 inch system with rear exit today, but if you add a blower tomorrow the exhaust may have been worth 10 HP (just a shot in the dark) It all depends on what else you have, what else you add. I am the Flowmaster Defender around here. I have built multiple 5.0's and Flowmaster is the only thing I have ever used because its never let me down. They do have some stainless options as well, check out their site at www.flowmastermufflers.com I'd say a 50 series is for you. Maybe even the 50 series with deltaflow tech. Its got good tone exterior wise, and quieter on the inside. You can hear soundbites on the website as well