Owned one of these for 2 years until I wrote it off on a corner! First Bim I had bought at the time (now on SB8), so it was a complete learning process compared to the faultless, but less involving Jap bikes I've had.
First thing to do is to junk the twin 6v batteries behind the clocks. These are always going flat & causing problems. The engine is restricted by the too-small airbox so this needs to be taken out & a Stage 3 Dynojet kit fitted. Where the airbox was you now have a space where you can insert a battery box which will hold a 12v battery. Much better starting from cold plus helps centralise the weight.
I replaced the standard underseat exhausts with a set of original Bimota race pipes, unbelieveably loud plus noticeable power increase. All of the above work was carried out by an ex-Williams F1 engineer who I was lucky enough to meet & who also owned an SB6. He had carried out further improvements to his bike, such as replacing the awful one-piece fibreglass fairing which fastens underneath the sump, with a 4 piece custom made carbon one, which made servicing & access to the engine much easier. He had also fitted Yoshi cams & a big bore kit, so that in a straight line the bike was as fast as my '99 R1!
You need to keep a spare supply of bolts handy as these tend to vibrate loose & fall out, particularly around the point where the carbon seat unit meets the frame spars.
It might sound from the above that I didn't really enjoy the bike, but in fact I absolutely loved it. The best handling bike I've owned (better than R1, R6, GSXR750) plus due to the low seat height, knee down around the corners on the roads, right or left, is just a given!
Attracted attention wherever you go & I just adored the GSXR1100 engine...absolutely bulletproof. One final piece of advice: speeds in excess of 140mph, the wind pushes the fairing back onto the headlamp mounts & starts to crack the fibreglass. Screw the headlamps as far back as you can with the adjusters to prevent this happening...& find an understanding MOT tester when they check the lights & they're shining on their ceiling! Good luck if you get one, it's like all good relationships...hard work but ultimately worth it in the end!