You've probably read over 200 exhaust stories and, right now, are wondering why we're doing another one. It's simple. An exhaust is usually the first or second aftermarket performance part anyone slaps onto their car. More importantly, a bolt-on exhaust system is a rather quick and simple install. And even more important than that, it makes power. Well, most of them do. We'll slap a Magnaflow after-cat system onto an '06 Honda Civic Si and see just how much power we can gain from a couple shiny pipes.
 1. Here is a look at the Si...  1.
Here is a look at the Si exhaust from Magnaflow. It's full stainless steel and straight through from end to end with 2 1/2-inch mandrel bent piping. |  2. The original equipment...  2.
The original equipment Si exhaust isn't bad for stock, but it's a little more restrictive than we'd like it to be. Plus, this one looks kind of tore up. |  3. With the car off the floor,...  3.
With the car off the floor, either on jack stands or a lift, loosen the two12mm bolts that hold the muffler section to the exhaust B-pipe. |
 4. Lube the rubber hangers...  4.
Lube the rubber hangers for the muffler and pop them off with a pry bar. Make sure you have the muffler secured or it will drop. |  5. We told you it'd drop....  5.
We told you it'd drop. Bring the muffler down and put it aside. |  6. Loosen the three 14mm nuts...  6.
Loosen the three 14mm nuts that fasten the B-pipe to the catalytic converter. |
 7. Again, lube up the rubber...  7.
Again, lube up the rubber hangers and pry them off. Remember to be sure you have something supporting it or the exhaust will fall. |  8. Once everything is loosened...  8.
Once everything is loosened and both hands are free, you can pull the B-pipe down and put it on the floor next to the muffler. |  9. Side-by-side the Magnaflow...  9.
Side-by-side the Magnaflow exhaust is much sexier from the stainless steel 2 1/2-inch mandrel bent piping all the way back to the straight-through polished muffler. |
 10. OK. Enough staring at...  10.
OK. Enough staring at shiny metal, line up the rubber hangers with the new B-pipe hangers. |  11. Fasten the B-pipe to the...  11.
Fasten the B-pipe to the catalytic converter using the three stock 14mm nuts. No new gasket is used on this setup. |  12. Slip the band clamp over...  12.
Slip the band clamp over the B-pipe section in the rear then slide the middle pipe into place. |