Iwannamakeknives,
What kind of SAR work will you be doing? It would help to have a better idea of what kind of environment you are going to be operating in.
There are several of us around here that have been involved with Wilderness SAR for many years. The hands down favorite is a Fusion Steal Heart particularly the Heavy Heart variant. Unfortunately they haven't been made in years and run $500 plus on the exchange.
Other knives that my colleagues carry are Ratwielers, SNFO, NSFNO, battle mistress of any and all variants. A few of us are using SJTACs also. A small minority of also have tried the Sasquatch. For the most part none of use have been impressed with the Sar series.
Outside of Busse Bill Siegle makes a four inch knife that was developed from input of River-8 and many of us SAR types helped do field testing on the prototypes. It has quickly become a favorite smaller knife around here. Another smaller knife to consider is a SST (also 4 inches) by Okuden. I bought one last April and have been doing a long term field test on it. I am really impressed with it.
Another thing to consider is what your department policies are. My friend was a pat timer and he carried a Game Warden as part of his turnouts. It was the largest fix blade knife his dept would allow to be carried. EMT shears, seat belt cutters such as Benchmade Houdini or Model 7 rescue, and a good high quality folder such as a XM-18, Strider, Benchmade, Spyderco etc... would serve you better in the long run and would be usable for turnout and SAR use.
Hope this was helpful.