underpressure02

I asked in the tech section but only got one reply and I need some more info.
I just bought a used AEM fuel rail and regulator. I am going to be installing it on an LS turbo motor. I just have a few questions. Do I need any type of gasket or does it just basically bolt on?
Also to adjust the fuel pressure. I am assuming I have my car running and first before I take my stock rail off and see how much pressure I have?
Then when I put the new rail on do I start the car see where the pressure is and then adjust it? Or does the car have to be revved up? Should I replace the O rings on the injectors when I change the fuel rail or is that not necessary. And also how do I adjust the fuel pressure. Does it stay the same whether it is at idle or at full throttle?
This is my first time ever installing a fuel rail so please no flames. If any one has a link to instructions or stuff to be careful when doing this that would be great.
Thank you