airceo13

Hey guys I just recently picked up a 1991 Ls400, has 325xxx kms on it. I've been reading a lot of the previous threads that were made, but I have been having some trouble finding the information I need.
I have a Nak system, everything is stock, but 3 of 4 speakers aren't working. I have played a blank tape and there were no hissing sound on the 3 speakers that arent working. I know that I have to replace the speakers with 4" or hack the box to fit in 5.25" speakers. All I need to know is whats the proper ohms I need to use? 2 ohms or 4 ohms?