My car mae 403 rwhp and 389 tq, and carried 400 hp rom about 5800 all the way up to about 6300, and the tq was over 350 from about 3500 up to about 6000, so the curve is really wide and flat.... killer good for a street car, and I'm sure it will run at the track as well. My car has a lid, qtp longtubes (non HV collectors ) a catted Y pipe, slp lm, pulley and ported TB. No elec water pump, t stat or maf yet... so with that stuff addd in too, I would probably see around 410 to 420, thru he heavy 12 bolt and a steel driveshaft. I'd guess that your car would see similar power with similar mods. As far as headers go, the best advise I can give you is go with stainless ones, a bunch more $$, but htey don't rust out, something that a street car will have more of a problem with than a race car. After that, I'd say it's either Kooks or QTP's. I went with QTP's whenI bought mine because they were in stock, kooks had a 4 to 6 week wait, and Barry from QTP was very helpful. If you do go with QTP's, I'd think about the Y pipe though.. it's a bitch to get in the car. Depending on who is doing the install, and what you are gonna run for exhaust after the headers, I'd saythat should be factored into the decision.
P.M. me back with what Eastside has to say, if you give them a call and if you don't mind.