has anyone heard of the 3'' exhaust made by Magnaflow? I think the kit comes with the magnapacks. Is this a good thing to do if i am supercharged?

 

yes and no, I feel you need to be pushing some heavy numbers like in the 700+ range to get the best benefit from the 3" tubes. Then what good does 2.5 headers do you then. See the picture? You would need to upgrade everything. So cost vs benefit, not worth it till your dead set on the engine combo.

 

A 281 cubic inch motor does NOT need anything larger than 2 1/2" unless is it HEAVILY modified to push some crazy high numbers and even then it's questionable.