Guys, I really waffled the factory steel tank on my 06 S. I ride 90 off/10 on-road. I would also like a little more fuel capacity so I'm considering the IMS 3.2 or 4 gal. I currently have UNI Biker rad guards. What are the negatives of the larger 4 gal model ? Does it effect how your knees hug the tank ? Tanks in advance !