Yep. JRE 75 Package + Headers tops at about 590rwhp in a M6 car, add a Vmaxx and you should be close to 600 and it will be exactly like stock just...faster
JRE 75 Consists of:
Cold Air Intake
10% Overdrive lower crank pulley (8.6")
ATI Balancer with your choice of GM or ARP bolt
Diablo box and free tune
Link to it here:
http://www.jreperformanceparts.com/p...-rwhp-package/
For headers you have American Racing, Kooks, Dynatech, and Stainless Works for the top of the line ones, and for exhaust, you should always go top of the line IMO. Set of the afore mentioned headers will be around 1200-1400$, less if you go catless and less if you can get them wholesale/used.
You can do up to 10% overdrive on the stock injectors. Some people (here comes Stunnah now) have run 18% on stock injectors, but it is a bad idea, and I think anyone would agree with that.
If you want to be making 600 and over then swap the injectors to ID850s (About another 900$) and do a 9.1" or a 9.55" lower pulley instead of the 10% (Which is 8.6"). If you want to run more boost than that, then you'll want to add a cam (Now we're talking 690rwhp and up from there).
At this point, there's a TON of options and information being hurled at you. I know what this is like, it was me less than a year ago, and I remember feeling like I was only getting half information, which is why I try to give more details in response to new guys. Feel free to ask detailed questions.
I'd wait for a little bit, make sure you know what you want, because ultimately, doing what you wanted the FIRST time will cost less money and end up being a better build.
Look around on this Forum, feel free to ask questions.