The 03 650 has a better air filter design that has more filter surface area. This means more power and longer riding before the filter is clogged.
I spent $100 on parts (excluding the air filter).
14073-1930 qty 2 needed, duct-air funnel (velocity stack)You also need seven 6x16 metric screws (forgot the pitch, but it is the same pitch as the fender screws).
No single part was very expensive, so don't try to save money on the airbox, since it was only $18.
I installed it and have run it many times since. It has a little more pep at all RPM's. It isn't much more, and might not be worth the money from a performance perspective. However, the twin air filter means better filtration than a K&N, and the 03 twin air flows better than an 02 K&N. Plus, the filter fits better and there is less chance of dirt getting by the edge of the filter.Just so you know, you need to remove the grommets, latches, short hose fitting (on bottom), snorkle attachment hose, and clear inspection bulb from the old 02 airbox. Also, there is no way you can convert the 02 airbox to use the 03 bracket and filter. It would just be a nightmare to try to modify one and the main box was not expensive (around $20). The lid is not interchangeable, the lip is the same pattern but the latches are moved. The stacks won't work at all either. The 03 stacks are actually smaller than the 02 ones.
Follow my list exactly, you should be good to go.
Here is my complaint about the K&N on the or airbox. It is not squeezed positively against the airbox lip all the way around. I don't like that. When I had one, I greased it to prevent dirt from enntering there.
