I still might say have a shop do it. I'm not sure if the exhaust sytem, in particular the cat is different on your year. On mine the cat is integrated into the stock downpipe. Thus by removing the stock downpipe to put on the piece for the header-I had no cat. It was just header, downpipe, collector and then nothing. I had to have a shop install a universal cat and weld it in. Then the o2 bung needs to be welded in. One o2 sensor needs to be before the cat and one after. Unfortunately the header was designed supposedly for the federal camry-(thats what i was told

) But in California emmisions are tougher and the setup is a little different. There is two 02 sensors. Thats why the second 02 bung needs to be welded in. Leave it to California.
If you don't have a new cat, any welding equipment, and a lot of patience just take it to a shop. It was a big headache for me-especially the 02 sensor. Best to get it done right from the start. Try to take it to a custom shop. A lot of places wouldn't even touch mine to try to fix it after it was installed because the header isn't carb legal. Where are you from?
Let me know and just ask if you need any help.