For a 97, if you run B100, you will have to replace your fuel return lines. The stocks are rubber and will melt over about 2 months. I replaced mine with teflon/SS braid - both lines totalled $27 but installation was another $150. I had to have someone else do it because of lack of time and proper tools. If you can do it, then you are only looking at a few bucks.
Running B20 you will not likely have to do this for a very, very long time although you should remove the plastic covers and keep an eye on them. B20 will also take much longer to clean your tank and lines. I ran B100 and never had a filter clog. It will just depend on the condition of your system when you start. It would be a good idea to have a spare with you regardless.
Other than the lines I never had a problem. My only problem now is supply. Once you go bio, you wont go back.