An oil change is very simple to do, and just as simple to screw up.
If I were you, I would get a friend who is knowledgeable about cars and has done many oil changes in the past to step you through it.
Also, since this is an Si and it might be your 1st oil change, take it to the dealer and tell them you want to watch the oil being changed. They should let you do that. Ask the Tech that's changing it questions each step of the change.
The reason I say don't do it the 1st time by yourself is this:
1. If you overtighten the oil pan bolt, you could strip the threads in the oil pan. (This is BAD)
2. You need to have a torque wrench to tighten it to spec, unless your familiar with the feel.
3. You need to know to lubricate the filter gasket before installing it.
Once you've done it, it will become second nature.
good luck
augydog