I have an OEM 1.8 2007 Mk3.
I have it booked in at Tony Banks for an exhaust to be fitted in early March.
The question is, will I be able to fit a twin tailpipe on each side or would I need to go for the single on each side due to space under the rear bumper?
Ideally I want the 4 tailpipes as I think it would look cool but if not enough room I will need to chose I nice single exit tailpipe on each side.
I reckon the problem will be with the rear skirt cut outs. With a little fettling there anything possible but probably costly.
There is a You-Tube clip of just that, a guy fitting four pipes 2 each side. He does it all himself as well, but he does have good weather, summer time. 
I did mine 9 yrs ago. But the tips were stainless from south Africa and they rusted so I had to paint the tips. But they do work with a slight cut to the rear bumper.
Tony Banks did this for my supercharged NA. I know it’s not a NC but shows what can be done by him. 
Another option, Safetymatch on here has a very nice back box on his NC, sort of two pipes but in one piece, each side. Hopefully he might see this and post a pic for you to look at?
Barrie
Tony Banks fitted a dual exit exhaust to my NBFL - one either side like the NC.
In addition to two or 4 pipes there are different shapes and bore exhaust tips available so its worth choosing these ahead of the fitting date.
My exhaust pipes (tips) are wider then the standard NC and I think they look perfect but of course its a personal choice.
Just an opinion.
As much as you want the 4 pipe exit, (and they can look very good) it is just as important that the rear diffuser looks right too. If you start cutting/bodging to make it fit, it will look bodged and naff perhaps. 
Likewise, if you go for the 2, a nice looking tail pipe would look great without going OTT.
For example, the attached picture. “It Looks right” for 2.
I don’t know, but is there an aftermarket diffuser that would suit your needs and “Look Right”?
Budget is a factor of course.
