B5 is no problem at all for anything in your car. In fact, anything under B20 is fine too. People trust this so much that if you've ever driven through Illinois and bought diesel at a truck stop, you probably got B11 without realizing it, since a number of places (A lot of Pilots, for instance) there are pumping B11 in all their diesel pumps without making a big deal out of it.

Even B100's fuel line and fuel filter issues are exaggerated. Most people's lines have been replaced at least once since the car was made, and anything made in the last 15 years is resistant to biodiesel. Viton is the best, but other things hold up well too.

If you are starting to use biodiesel, don't do anything to your car at all. Just keep an eye on the lines every so often (pop the hood every other fill-up or something), and check for weeping or cracks (you should be doing this regardless of biodiesel use, actually), if you see either of those things, then replace the lines soon. Then keep a set of filters in the car so you can change them if/when they start to clog. They probably won't, and if they do, you'll have plenty of notice (namely some hesitation at high speeds), and then you can change them when you get home. I've got nearly 15,000 miles of biofuel use (average of around B20, lifetime) on a set of filters that I installed when I got the car.

peace,
sam

__________________
"That f***in' biodiesel is makin' me hungry."

1982 300TD Astral Silver w/ 250k (BIO BNZ)
2001 Aprilia SR50 Corsa Red w/ 5.5k (>100 MPG)