Yeah, the coupling just connects the throttle body and charge pipe together.

I don't really know what to tell you. Your best option is to install the blue box and avoid boost until you can get it tuned. The stock ECU will throw you codes left and right and you will lean out to the point of engine damage. The P28 may work without codes but I would put the blue box on and be real easy on it if you HAVE to drive it.

You will need a blow off valve if you want to maximize the life of the turbo and it's thrust bearings. It will also spool up quicker after shifts since the compressor wheel isn't slowed down by the pressure waves that send it oscillating against it's thrust bearings. I didn't have a BOV for 2 weeks after I installed the turbo, so you can wait but I wouldn't be boosting hard until you get one.