I just bolted on my magnaflow today, its a little bit louder and a lot deeper but i'm wondering if theres any hp gain. My car's totally out of tune right now and isn't running to well so I can't tell. But i've heard its one of the best flowing systems out there.

 

There is a decent gain over the old stock set-up...

 

for exhaust i would assume technically its less loss then any gain...
but i could be wrong...

 

Magnaflow is a great stainless steel 3" cat-back...and the best priced as well (~$300 shipped)...

If this is a step up from your stock 'cat-back' then you'll definitely see a hp/torque gain....and those #'s will increase somewhat depending on what other mods you may already have or may get in the future...

 

I bought it off ebay $280 shipped

 

I gained 26 RWHP and 14.6 RWTQ, after SLP CAI and Magnaflow catback.

Stock, car did 238 HP / 275.3 TQ in January of '03
After CAI and Cat-back it did 264 HP and 289.9 TQ in July of '03.

 

I noticed a small SOTP gain from my Magnaflow, but nothing significant. The previous owner of my car had put a flowmaster muffler on...I just thought I had loud stock exhaust . Headers are going to be the big gain when it comes to exhaust