just wondering if a higher flowing exhaust wil cause better or worse gas mileage...

also with a de screened MAF ? would that cause worse gas mileage?

 

I don't know that it will hurt your mileage much, but IMO flowmasters blow. I had 2.5" duals on my Impala and they sucked compared to the Magnaflows that I put on. If you're after sound then go for the flows, but for performance they are crap in my book.

I don't think you'll see any change in mileage from either mod, maybe more since air is flowing easier.

 

A better flowing exhaust system will actually help increase your gas mileage a little...

Mike

 

I took off my flowmaster American thunder cat back and picked up 4mpg.
I couldn't believe it

 

it isnt actually a flowmaster, it is an outlaw, basically the same thing as flows tho they are just 1/2 inch shorter to avoid the copyright law..... but i like the sound feels pretty good, but i will be upgrading the exhaust later, after i get the LT's