I think you could make your FZ into a track bike but if you plan to attend track days regularly you’d probably be happier with a 600 SS bike. The SS bike has the correct ergos and a better suspension out of the box. Getting your body out of the touring position and into a track position isn’t cheap. You’ll need rearsets and clip-ons of some type. And as stated you’ll need at least R6 forks and I’d highly recommend a quality shock; Ohlins, etc. Just those items are about $1,000 to $1,500. You can buy a nice used 600 SS track bike for about $3,000 to $4,000. For that price you’ll usually find a nice suspension, brake goodies, steering damper, track body work, safety wired, etc. An SS bike also nets you a better frame, swingarm, rearsets, clip-ons and race saddle. It all depends on what you want to do.