if its a r33, you need to take off the 'skyline' bracket off first. This has 4 screws plus a middle plastic thingy, need to pop that out too.
then unscrew the screws on the tail light and slowly pull it out, pull it from side to side, wiggle it. or from the inside, use something to hammer it out from the screw. Or use a screw driver from the outside and pop it out, best point to pop it out is the indicataor, where it seems like the light has been chipped. (weird how i;ve found alot of skylines at that particular point, seems chipped)
the glue isnt so bad. knock it out
i did