All the Intake Mods without Exhaust

[BigED]

I have an SLP CAI, K&N Filter, and a Whisper Lid on my car with stock exhaust. I noticed a big difference in sound, but not a big difference in performance. (I know the gains shouldn't be huge, but I figured they would be more noticeable than they are)

Anyway, I was thinking on getting a dynomax muffler, and I wanted to know if I'm neutering my intake with a stock exhaust and if when I put a new one on is there going to be a big difference.

Also, will just a performance muffler help, or do I need to go a whole catback. I definately want dynomax, because they are cheap and they sound good. If I need a catback, what pipes do I need in addition to the muffler and what diameter. (I know that muffler diameter is a widely discussed topic, but I forgot if the ideal for a 3.8 is 2.5 or 2.75 - 3 would be overkill, because I'm not planning on nitrous or superchargers, etc.

Will I notice a big difference between adding just a muffler and adding a catback?

[Guardsman]

Any changes to the exhaust will be noticeable. I just replaced the stock tailpipes with WS6 tailpipes (stock is 2.25", WS6 is 2.5"), and it made a noticeable change in the bottom end torque.

[Only4U]

well, contradictory to what everyone else believes, i don't think you'll notice much of a difference. yes it will be better and yes you'll notice it, but it's not going to be anything huge. about the most hp you can get from an exhaust system is 10-20 hp (what they say) and about the most you can get from an intake is about 20 hp (also what they say). personally, i don't think either give you that much...maybe half or a little more; so, i'd say you are looking at about 15-25 extra hp from intake/exhaust mods. i could be wrong, but i do know that exhaust mods don't really make that much of a difference because i bought an $80 magnaflow on my car and raced my friend's standard (3.23 v 3.08 gear ratio) firebird with a $350 exhaust sys on there and i beat him. so, it's obvious the expensive exhaust didn't do a whole lot more for him and the sounds are identical. but i'm just trying to give you an answer and keep you from wasting your money on something that the cheaper ones will benefit you just as much with.

[BigED]

If I saw 20-25hp with everything I'd be happy.