You can go to cdc and download the instructions and templates. There are different holes for 90 and up. You need to remove the rear seat and inside 1/4 panels after you've drilled the holes for the bar. I've installed a few and you should fab up some brackets to mount the bar to. If you just bolt it in, you will notice it flops around. Is it a styling or a light bar? If it's a light bar you also need to hook up the light to the 3rd brake light wiring.
it's just a styling bar. as far as where it bolts up, i'm figuring it out based on some instructions i've seen online, it's just a matter of removing the seat, the 1/4 panels, removing 2 bolts on both sides and installing it with longer bolts I assume right?
i just read the cdc instructions, they are the best ones i've seen. Install seems to be pretty easy. the only hard part will be cutting the holes without the template.