Definitely go with a Pro Design clamp on kit. The stock design is too flawed to work right, the opening on the filter and airbox are mismatched by about half an inch so the flow is turbulent, and since the airbox lid holds the filter in place, it's much easier than it should be to incorrectly install the filter and unknowingly suck in all kinds of dirt. Don't get the modquad clamp on kit either, it may look similar and cost a few bucks less, but they're ****. I got one and had to get a different filter to even remotely fit in the airbox and it was still a hack job by the time I got everything together.
Whether you go with a UNI or K&N filter is up to you. The amount they flow is too close to the same to really let that effect your decision. There are always a lot of opinions involved in the answer to this question, but to me the K&N will always be my choice. Some claim the UNI filters dust better, but I never saw proof and never saw evidence of my K&N filters passing dust even in the most extreme conditions. I personally think the K&N filters are much easier and less messy to clean and re-oil than a foam filter. Just spray, rinse, let dry, and spray the oil back on. Probably less expensive in the long run as well, a K&N cleaning kit runs about $10 which should last for about 4 cleaning cycles if not more, a can of foam oil alone costs about $10 and usually doesn't last as long, and you still have to buy a solvent to clean the nasty sticky oil out of it. Then you have to re-oil and massage it all through the filter to get it covered evenly. This is the part I hated the most about foam filters, because there's no way to know how much more oil you need to use, and if you have all the areas covered. I usually ended up over-oiling it in fear of not having enough or missing a spot, then the oil runs into your airbox and makes a sticky mess of that as well.
