I know everyone says buy the mandrel bent exhaust but if you were to have house of mufflers do it with a 2.5 inch the way they do it, is it bad for your cars performance or is mandrel just that much better. can you guys just give me some info on the differences and benefits.

 

You can have crush bent or mandrel bent.

Crush bent is ok for NA model Volvo's, as you want to maintain backpressure. Mandrel bent is good for turboed Volvo models, as you want a free flowing exhaust system.

Mandrel bent flows a lot better then Crush bent.

Just like if you were to buy an exhaust system for a NA model you don't want a straight through design muffler you want one with baffles in it like a Flowmaster. However if you were upgrading the exhaust on your turbo model you want free flowing, so you would want a straight through design muffler like a Magnaflow.

"The mandrel bender allows the exhaust pipes to be bent into smooth curves without undesirable creasing, kinking, or collapsing."

"Mandrel bends maintains the same ID all the way through the bends. Crush bends are just like they sound; the piping is crushed slightly while bending, decreasing the ID of the pipe. Mandrel bent is the preferred method, but requires special equipment. Virtually all of your local muffler shops can only crush bend."