The hardest and longest part of the installation was the first step, getting both the Z3 and the new exhausts to the installation location was more difficult than I thought it was going to be. There was no way these big things were going to fix in the Z3. They also did not fit in the trunk of my wife's 318i, luckily I found a way to fit one in the back seat and another in the passenger seat. I ended up having to drive the 318i (carrying the exhausts), then drop off the exhaust, then return home, then drive the M roadster to the shop, install the exhausts, drive the M roadster home, return with the 318i, load up the stock exhausts and them drive them home. I probably spent more time driving cars around than it took to actually install the exhaust.

The actual installation process was very easy, but before I could start I needed to let the exhaust cool off. During the installation process you will be holding some parts of the car (like the muffler) that get quite hot while the car is running.

Once it had cooled down the first step was to remove the stock exhaust. There where 10 bolts in total (5 per side) holding the stock exhausts in place. On each side there are two bolts mounting the exhaust to the catalytic converter (top right), two bolts holding the rear of the exhaust in place (bottom right), and one bolt in the middle (middle right).

I should point out that the exhaust is actually held in place via some rubber hangers that allow the exhaust to slight move and adjust in normal operation. The bolts I'm referring to attach the rubber hangers to the car.

Instead of removing the rubber ring that was holding the middle of the exhaust in place, I decided to remove the bolt that holds the bracket that the rubber ring is mounted on. This made lowering the exhaust a little easier. I started by removing the rear bolts first, then the middle, and then the front. But I had someone holding the rear (muffler) exhaust while I was doing this.

The only part I replaced (at the advice of Larry Nissen - BMW tech) was the ring seal that fit between the cat-back exhaust and the catalytic converter. Larry didn't think this was "necessary", but it was possible that a exhaust leak might occur using the old rings, so we decided to replace them just in case.

After one last side by side comparison it was time to install the Remus exhaust. I was quite impressed at how easily and precisely the Remus exhaust fit into place. Starting with the rear bolts first (while someone held the front of the exhaust) the new exhaust was put into position. The first pass the bolts were left loose, a second pass tightened them all down. The only part of the installation that wasn't smooth was the support that had become bent in shipping. But after a few whacks with a hammer it was bent back into position and the installation was complete.

Once the Remus exhausts were installed I took a look at the exhaust tips to see how centered they were in the cutouts of the rear bumper. I was concerned that an off center exhaust tip might melt some of the rear bumper because I have seen that happen with some aftermarket exhaust. But I was relieved to see that the exhaust tips were perfectly centered in the cutouts. The Remus exhausts really were a direct replacement, practically plug-and-play. They fit precisely in place of the stock exhaust without any modification. But now that they were installed the next question was, "what will this do to the M roadster's performance?"

Performance