something to consider is the printer. Since we have two different large printers using two different RIP programs colors aren't the same when exported as RGB or CMYK. If it's vector art no worries. Anything raster we send to one printer as RGB. The colors are much more vibrant and rich. And don't use C0 M0 Y0 K100!. The file size is much smaller too. Depending on the actual dimesnions of the finished product we won't export at 300dpi crashes the software every time. As a rule we try to keep the file size under 200MB. One printers RIP converts the colors differently so we export as CMYK.
my 2¢