I installed the extractors and cats myself today. From the bottom, I never intended to put them in from the top. Bit of a misunderstanding there I guess.
Few tips for ppl who are looking into this in the future:
1. The stock header bolts are 1/2", soak them in CRC for few hours before trying to loosen them. I soaked them for 5 hours before I went out then came back.
2. You don't have to remove the plastic covers on the firewall on the passenger side, there's plenty of room as long as you jack up the car as much as possible.
3. Driver side is much harder, the steering column needs to be removed and zipped tied up and aside, but there is a big black rectangular wiring loom plug in the way above it, next to the booster. Pull its locking tab out, then disconnect it, swing it aside, and then the column can swing up enough.
4. The dipstick. It was the BIGGEST bitch of a thing for the whole job. It goes down between no. 3 and 5 port, and tucks JUST behind the engine mount to reach the hole in the sump. So with the new extractors, put it in position, hook up the cat back loosely, then feed the tube down between no. 3 and 5, then between no.1 and the block, then JUST behind the engine mount bracket to reach the sump. I wasted at least 2 hrs just to figure it out, as I was taking it off and put it on, putting in and take out, look on top and go under the car etc to figure out where I was at. Almost decided to remove the starter and bend the tube to custom fit it... Lucky I didn't after some careful observation and a helpful desk lamp!
5. An extra pair of hands and eyes will go a long long long way for this job, refer to last point. It will half your effort and work time, trust me on this! I was working by myself completely, without a hoist, had no idea what I was doing, and I spent 9-10 hours working on it. Thank god its all over!
6. Wear mechanic gloves!!
7. Get a new set of leads and plugs before hand like I did for back up. As I presumed, I got a miss after completed the job. I think a lead is gone during removal. They have done 85,000km so they are getting fragile. Will change them tomorrow.
After all, it is well worth the effort. Good experience for myself and now I got a car that sounds like a real V8. Time for a tune in 3 weeks!!