Bottom of fan
Brackets on either side to prevent rubbing, mounted to top/bottom mounting holes in the radiator. I also changed the location of the temp sensor and mounted it to the bottom of the upper radiator hose.
Top strap, bolts to hole already in the frame.
I mounted my entire set-up without drilling any holes in the truck. I did drill some holes on top/bottom of fan for the strap mounts. I also used some zip ties (heavy duty) to pull the fan to the straps on either side that keep it from touching the fins just to prevent any rattling that may have occurred.
Had mine going for 4 months or so and haven't had any issues. Go with a 130 amp alternator, I love the amount of power mine has.