I love handling my nighthawk and i have some experience to. I can outturn a gsxr1000 on the turns...
I would first recommend removing the mirrors, taping the lights, take off all the turn signals, get a set of new tires, and get a race stand. With my bike i have shorty turn signals and a streetfighter mirror for daily traffic. The race stand you will have to drill and weld the spools in and you can take off your original kickstand for the time being since i have drug that before...
With tires i would go with the Dunlop D208 Supermoto for the rear.
http://www.bikebandit.com/product/3463
It will be a bit slippery when cold but i dought that you will beat on it when its still cold anyway. The front tire is fine, just make sure it has plenty on tread on it. Those are the tires that i am using on and most of my racing happens on the street anyway.
Now for bars, i HATE the supercross bars and actually want to go away from those. I haven't seen any clip-ons since the tank is buldgy and the fork is low. I have, however, found clubman bars that look good...but i haven't ordered them or riden on them so i couldnt tell you there but you can find them for dirt cheap on ebay going for a round 20 plus shipping. Those have the bent down look and thats what i want.
Have you looked into performance? There are a few things you can do to the bike for almost free (on this site).
I'm thinking about getting the Vance and Hines megaphone exhaust sonce it went from 500 to 300 and then also pick up a dynojet kit. A Tim hodge exhaust mod and radio shack washer trick would probably also help almost as much for....free...
I would also look at your brakes. I run EBC pads that i have burnt through all year and they are still riding awesome. Make sure you just dont overheat yours (thats why i went with ebc and they lasted forever) and before that track, i would bleed them and put Dot 4 repsol brake fluid in them. I would also get a stainless line (mines in the mail).
And if you want to go even farther and crazier, I took a adjustable brake level off of a gsxr and put some bondo on the end to fill in a small gap and with about 10 minutes worth of work and a night of waiting till it dries, you can have a custom adjustable lever as well. Its a little tricky to bondo but its so worth it in the end..