2006 S40 Exhaust back pressure/ exhaust shop question

POSTING FOR A FRIEND:

Have a 2006 Volvo s40 with a inline 5 (2.4L) Originally had a cutout about half down the exhaust system, which gave a great sound, but I lost too much back pressure.

What are my options for a built exhaust that is as close as possible to straight pipe sound with enough back pressure? Would straight pipes running entire length of vehicle provide enough back pressure?

And... yes this car is very slow... Not a fast car, just a good looking euro faggot car...

With that said what would be a good place to get this gay work done?

And I'm serious about this question, just fully aware a Volvo is not fast (at least the ones without turbo such as mine...)

Don't think longer straight pipes will add any back pressure, a decent high flow cat should do what you want, will be a little bit muffled but still better than stock

Oh boy....

What your friend is looking for is an exhaust that scavenges the exhaust as it released, and not one that has a magical balance of "back pressure".

New pipes with an expansion chamber that features a larger opening for the exiting pipe of the chamer is what he is looking for, this acts as a one way check valve to allow the exhaust gases to continue flowing away from the headers and heads and out the back.

There are tons of posts on here that disprove the notion that a NA engine exhaust system require some form of back pressure.

Read this and be educated:

http://www.gomog.com/allmorgan/exhaustbackpressure.html

Needing exhaust backpressure is a myth.

The exhaust is easily capable of changing and/or moving the power curve. Did a bit of real testing on this and it was pretty obvious that larger exhaust gives more horsepower up top, and it's mostly a function of moving the torque peak up in the rpm. So you lose low rpm torque, but gain up top. Great for race cars, not ideal for street cars.
Backpressure is a long misunderstood thing,and often used in sentences when exhaust size is discussed.
Good exhaust will make good top-end power without costing a bunch in the midrange, but there is no free lunch.