Steering dampner: A frame mounted one is cheaper, but susceptible to damage in the event of a crash. Do yourself a favor and spend the $60 and put some frame sliders on your bike. Probably the cheapest form of protection you can get.
Leathers: Vanson, SPIDI,Dainese,Kushitani,Spyke,Syed, Z-custom,Teknic. I hear the KOBE leathers carried by Marrieta Motorpsorts were decent (and cheap $799), but I saw them at the motorcycle show and wasn't impressed. When your ass is sliding on the pavement at 90 mph, you want the good stuff, beleive me. You should expect to drop between $800-1400 new, or around $400-800 used for a set that hasn't been pre-crash tested much.
Suspension: Send the forks to Max Macallister (or, wait until you have done some riding before you mess with suspension.) Typically you will put stiffer springs in the forks and if you want really sweet forks, have them re-valved as well. I knocked 2 seconds off of my lap times just by having Max put new springs, seals and fluid in my forks.(I couldn't afford the have hime re-valve them as well) New springs, seals, fluid and all labor totaled $275.
For the rear shock, I bought a Fox shock. You can adjust the ride height (I added 1 1/4 inch taller shock height in the rear) This will make your bike turn in quicker. I also dropped the front forks (lower) about 8mm. You don't want to drop the front too much, you will lose high speed stability.
Suspension is the tricky part. Understanding the fundamentals will help you understand what will happen when you make adjustments. Pre-load refers the spring pressure, more preload will make the front/rear suspension stiffer. Preload tightens/loosens the spring. Without the internals to control rebound/dampning, your suspension would be like a pogo stick.
Rebound controls how fast the forks/shock recover from being compressed. I believe rebound is an adjustable orafice that the fluid flows through. Enlarging or shrinking the orafice will change how fast the fork/shock can get back to standing/sitting position.
Compression slows or speeds up how quickly the fork/shock can compress. This part works like the rebound adjustment, it has an adjustable orifice that shrinks/enlarges to increase/decrease the ease of the movement of the "plunger" to go through the fluid quickly or slowly.
Finally, setting the ride height to you is Key. Go to www.traxxiondynamics.com
and read some articles about setting your "sag." This is very important.
Man, I feel like I just wrote a frickin novel or something! I hope I didn't confuse you about suspension. I used to be like Cole Trickle in Days of Thunder where he knew nothing about cars and how they work. I decided to learn and now I know a bit more than I did a few years ago.
Good luck and I hope I have helped you a little.