I used a K&N Filtercharger njection Perfomance kit # 57-3506, it is a sri made for the DC2.
All that has to be done pull out the old air box and put the new filter in, it uses the stock pipe and it is about an hour's woth of work, if you diy i recomend the use of an air wrench.
This does change how it sounds but it gives it a nice roar.

Heres what it looks like when its done