The last thing in the world I want to do is dis anyone over their chosen modifications. They do work for them so they must be just fine. On the other hand, if I firmly believe there are safety issues I would be remiss in not expressing my concern. Perhaps some people may think my opinions are motivated by some promotional consideration, I doubt people who know me will think that. At the end of the day, we can all come to our own conclusions.
I ride with a lot of Bandit folks and the rider skills of the owners of these bikes is the most diverse of any other bike type I know. This past spring a really nice guy was out on one of our rides with his Bandit Street fighter that included these mods (lower busa forks and the shock). on a down hill sweeping turn, riding at a moderate but fairly quick pace following several other bikes including stock Bandits he encountered a dip in the road just near the apex and crashed, fortunately he was relatively OK after sliding into the guard rail. it looked like the header system hit the ground, unloading the front of the bike. Another friend who swore by the Busa shock mod on his Bandit was behind me at a track day (I was working as a control rider) and on the first lap with about 15 other bikes in line got on the gas and low sided his bike to his total amazement. He was going the same speed as the rest of us (quite slow) and is a better rider than most. He still blames the tires (Dunlop Qualifiers) but I was on the same lap with the same tire temperatures running Michelin race tires and had TONS of head room traction and lean wise.
Suzuki engineered the Bandit with a specific amount of wheel travel and a ride height and steering geometry to suit. In doing so they consider things like clearances, chain pull and dynamic steering geometry and need these to work in harmony under a wide range of conditions. On race bikes, changing these type of properties on a bike, we proceed with great caution and the racers will tell you, even a small set up change like adding 5mm of rear ride height at the shock can totally change the handling of a bike. Sometimes these changes are good, sometimes not. A change like that may work at one track but not another. To add 20 mm of shock length and close to an additional INCH of travel to the shock? That is a huge, I mean crazy big change. Perhaps the Suzuki engineers are not so smart and this is the greatest improvement you can make. My advice is only that you be careful and try to scientifically consider the changes you are making. I really enjoy meeting and riding with all my Internet forum friends and would much prefer seeing them err on the side of safety.