If you can afford to spend the money then I would wholeheartedly recommend getting the full Tyga system with one of their end cans, they have a good range of sizes and styles of can from a stainless one that looks very much like stock, through carbon cans, to the maggot which I run. Lots of people cut their original systems and get links and collars to fit an aftermarket can. As has been said before by myself and others, if you have a tidy all original uncut system then hold onto it as they are going up in value, and get a pre-cut one off ebay. Have a look at Cammo's guide to rejetting carbs it covers the most common mods people make to their carbs on the NC30 i.e raising the needles by 0.5mm, drilling the slides, and rejetting to suit can and pipe. Here's a link to the thread:
viewtopic.php?f=24&t=14524
And a quote:
"Standard jet sizes are: 1989 Jap model (4 x 110), all other year Jap models (2 x 115f, 2x 118r), all UK bikes (2 x 120f, 2 x 122r). 1989 Jap bikes run very lean from the factory, best to rejet as a precaution. Other year Jap bikes will need rejetting if you run any non-standard parts (pipe etc).
Main jet sizes: If you run a nice sounding aftermarket exhaust and/or pipe, then the common consensus is to run 118 size front and 120 size rear (often referred to as 118/120). If you run a very high flowing/loud exhaust or full exhaust system then you may wish to consider running 120f/122r size main jets."
I now run a standard induction system: OE filter and no modifications to flaps or snorkel, full Tyga system with a Maggot end can, raised needles and rejetted carbs to 120f/122r which helped heaps in smoothing out power delivery across the rev range.
I am sure somebody else will give you a run through of how to fit an aftermarket can and what is available.