Hi all, I am about to install a set of 1 3/4" extractors with high flow cats myself next weekend. Just wondering if anyone who has done it before himself would like to share his tips and experiences with me. So far the plan of attack is: - I will soak the header bolts in CRC for 1 hour or 2 before undoing. - Undo all leads and flip them back so they are out of the way. - Undo all header bolts but leave 2 in loosely. - Jack up the car on 1 side, undo the cat back bolts and disconnect the O2 sesor plugs. - Leave the jack under the cat to take the weight. - Back to the top and take off the 2 last header bolts. - Carefully drop the whole thing down and then remove them from under the car. - Take out the o2 sensors and put in the new extractors. - Reverse order to install the extractors. - Connect the o2 sensor plugs with extensions and bolt on the high flow cats then the cat back. - Put leads back on and finish! I have also bought a set of leads and plugs, just in case... I had a quick look just then and was wondering: 1. If I jack up the car as much as I can on the side I am working on, (~400mm) I should have enough ground clearance to remove the headers together with the factory cats as 1 piece from underneath yeah? I just want to save the headaches of separating them. 2. The rear bolt on the passenger side header, it seems very close to the strut tower body work and firewall. I have angled and dished ring spanners and sockets too, will they be enough to remove the bolt? The room for movement seems limited, as well as getting onto the bolt. 3. The driver side header is close to the steering column and chassis rail. Can it be removed from underneath? 4. The dipstick tube, it needs to be removed before the driver side header yeah? I can see a 14mm bolt holding it on top, once I remove it, can the tube be pulled out of the sump as is? 5. Pre Cat oxy sensor wiring, I have to access the connection plug from underneath yeah? I can only see the sensor and wire on driver side. I bought 2 extensions for them. 6. Once it is all done, I know the Check Engine light will be on. I have been told by APS that is not harmful and the car will drive as normal. How long can I drive the car for though? Any other tips and advices that you guys may wanna share from your own DIY experiences are more than welcome!