Lots of threads discuss the surface condition of hulls, and how to make them fastest. But, many cats have stickers or graphics on hulls, usually near bow. And, many hull shapes are fastest when part of, or most of the bow, is submerged (e.g. to get transom out of water).
So, does anyone think these graphics, or at least the disturbed water flow on the front edge of them, affect the boat speed?
Or does the psychological advantage of having a "cool boat" outweigh any reduction in speed?
I dunno, but FWIW I believe all the Americas cup boats used waterslide decals applied underneath the top coat of glass.
You know the ones you used to accidently rip in half when you were putting the finishing touches to your 1:24th scale model of a 32 ford coupe hotrod when you were a kid?.
But anyway, i'm no expert on anything but i'd almost guarantee the performance of your 2up catamaran would be unhindered by the surface deposit/height of computer-cut vinyl graphics.
If it does concern you, you should ask your signshop to use 3M 3690 hi-spec vinyl. I'm pretty sure it only comes in white, so you'll be up for digital imaging/printing costs as well. It is the lowest surface height vinyl (0.05mm) that is available to the average joe on the street.
Well there maybe something with a lower surface height, but once you stick this vinyl to something it DOESNT come off - Just ask the Auckland parking warden who ticketed my car for being 6 minutes over the elapsed time of my parking meter.....on a large empty street on a saturday!.
Which brings another question - Just how hard would it be to drive your car when there is a 1000X700mm opaque white vinyl sticker over the drivers side of your windscreen? 
Well my vote is for everyone to add as much graphics as possible to the hulls..........I'll leave mine naked. 
I'm of the opinion that it doesn't cause any noticable speed degredation.
And if you're gonna come in last, you might as well look good doing it anyways 
I suppose the short answer is yes it will have some effect on the speed of the hull through the water.
Realistically though, the effects would be so negligible when compared to going the wrong way up a work or having a wineglass in the spinnaker or even having half a millimetre more or less prebend in your mast.
Happy sailing!