the gp160 is a good engine - seen/worked on one that is on a pressure washer at a truck depot. used by 50 different people, has had diesel through it, water through it and it still goes well.
please put a photo of a gp160 and a briggs cr950 side by side - they are pretty well identical. pretty confident that you can't directly get a cr950 from briggs but if you can find one in used good nick its an option. I have a cr950 on a pressure washer (actually a rs950 but same thing) goes well, can be a little hard to start if the weather is a certain temp (but its probably because of the pump resistance).
also have a 127cc briggs xr, very decent motor. Bottom dollar for one of them around here is $425
