B20 is drop in.
B100 will have cold flow problems if your ambient temp gets close to 50 degrees F. A pre-pump filter will need to be heated and biodiesel compatible(no rubber seals and bio friendly adhesives on the element.) Any hoses need to be teflon, viton or poly-propylene, no 30R7 rated hose that most parts stores sell. Tanks can be carbon steel as long as they've never had water contamination, which is very hard since #2 is VERY dirty and high in water content. Aluminum is optimum and plastic needs to be poly-propylene.
This is all my opinion from my own experiences and many phone calls to different bio producers and filter manufacturers.