Megan Racing header install and review with pics.

[Herbicidal]

Initial product impressions:
Overall I like the fit and finish of the header. It has a nice thick flange that will not warp and the welds look good on the pipes. The bends are less extreme when compared to the original - see pictures below. It came with a new gasket which I used. I looked at the original, which was in good shape, but I felt it was better to use a new one than to reuse the old that was conformed to the original exhaust manifold. It's really too bad that the Megan header is almost completely hidden from view at the back of the motor.

Removal:
Removing the old exhaust manifold took some creative finagling to reach some of the bolts. I was able to remove some from up top, and the others while lying under the car. I used two jack stands and a floor jack to safely keep my car in the air. I found an air powered ratchet was able to reach into some of the tight spots and had enough power to remove the nut/bolt when I didn't have enough leverage to do it by hand. One big downside for me was that the original air/fuel sensor became fused with the original exhaust manifold and I could not get it out. Eventually, with the help of my Toyota mechanic buddy, we were able to, but the threads were destroyed in the process. Which led to an additional $175 expense for a new sensor. Take great care in removing the sensor. I would suggest completely removing the old exhaust manifold first, then try to remove it. If it feels like it's getting stuck, don't force it! Get some penetrating lube and spray it around the threads and let it soak for several hours, then try it again. You may have to repeat this process several times. Take care not to get the lube on the senor head, keep it only on the threads. Hopefully you will be able to reuse yours.

Install:
I did a dry run test fit first to ensure I placed the new gasket in the correct position and that all the holes were lining up. I was disappointed to discover that I was not able to reuse the Toyota factory spring loaded bolts where the header connects to the mid-pipe. My Toyota buddy said that connection is designed to flex and now it's a solid connection. Also Megan provided only two studs that were threaded at both ends and only one nut for each. And, they supplied a single bolt that looked like a longer header bolt. I needed a total of three, so I went to the hardware store and bought two more of the same length and thread pitch. Megan should have supplied all three to replace the originals since the header flange is way thicker than stock and the gasket is thicker too. I was not comfortable reusing the original exhaust manifold bolts because of how little thread would actually go into the block. Regarding thread pitch, Megan should have also used the same Toyota thread pitch on the flange to connect the header to the mid-pipe for reasons explained earlier. On my sedan, I have a triangle shaped bracket that mounts with two bolts to the engine block and one to a bracket on the header. Again, the thread pitch did not match Toyota's, so I was not able to reuse one of the Toyota bolts for the bracket. I ended buying one that did work. In my opinion, Megan should have supplied three longer header bolts and made the thread pitch the same as Toyota's on the triangle bracket and the flange to connect to the mid-pipe. If they had done these two extra details, this would have been a flawless install. Once it was all back together I picked up the new air/fuel sensor from my buddy (it took two days to order, then receive the sensor) applied some anti-seize to it and using one of his sensor sockets, reinstalled it without issue.

Initial driving impressions:
I left the negative battery cable disconnected for two days while waiting for the new air/fuel sensor. After installing the sensor I reconnected the battery cable and fired the car up. The car ran smooth with no leaks that I can tell. I don't feel that I lost any low end torque, it seems about the same in the 2,000 - 3,000 rpm range as it did stock. Starting at about 3,000 rpm the engine feels like it's revving quicker than before, in fact the car feels more lively from 3,000 to redline. I'm kind of 50/50 on whether it was worth the money, especially since I had to shell out an additional $175 for the air/fuel sensor. A header is really just one piece to the overall intake and exhaust system and I believe to realize the full potential of the header I will need to upgrade the air intake with either a CAI or higher flowing filter using the stock air box. Also, the exhaust components from the mid-pipe back to and including the muffler could be improved as well for less restriction. I doubt I will replace the 'cats' as I imagine that would be rather expensive.

At this point I have not even run through a full tank of gas so I don't know if there will be any change in my gas mileage. I suspect it will be a little worse this tank as I've enjoyed keeping it in the 3 - 5,000 rpm range. Here's some pics to round it out.

Top side of new and old:


Underneath side of new and old:


Looking up at back of motor from underneath after removal of original exhaust manifold:


Looking up into Megan header:


Looking up into the old exhaust header:


Random bolts: The outer ones are the Toyota OEM spring loaded bolts that I was not able to reuse because the thread pitch is wrong on the flange to connect the header to the mid-pipe. The two threaded 'studs' next to them only came with one nut each, I ended up buying two more nuts. These replaced the spring bolts. The three bolts grouped together in the top center are the original header bolts, which in my opinion were too short to use again. My header came with only one longer bolt (the lower grouping of three in the center) so I bought two more to match.


Header connection to mid-pipe:


Looking up at header from underneath:


Looking at header from the side of the engine compartment: