Good ideas all.
I use the Suzuki tool and it works great but it seems identical to other available tools. Strap wrenches work too and, if you don't have one, it might be a good investment anyway.
Point of caution: Suzuki recommends that you install the filter by turning it two (2) full turns (720 degrees of rotation) after the gasket touches the base.
It would be hard, if not impossible to do that without a tool of some kind.
A leak would be a really bad thing because it would drop oil directly in front of the rear tire.
Also, if you use a K&N, it has provision for safety wire (a hole in the nut on the end) to keep it from coming loose. I recommend that you use it. If done well, it lends a certain "race bike" credibility and looks nice.
If you use another brand, including Suzuki, filter, put a hose clamp around it, tighten it, and safety wire the hose clamp to the frame to keep things "safe". (that must be why they call it safety wire)
I use stock filters with a hose clamp and safety wire with good results.
Good luck,
Dave