There's a new "direct fit" SD (Siemens Deka) injector for LS2/LS7 vehicles, and the beast flows pretty damn good! At 54# that is approx. 12# more than the LS7 injector. This should supply enough fuel on a supercharged GM application to at least 625 to 650 rwhp Actual, and probably 675 to 700 rwhp on a turbocharged GM application. I think it is the one I will be going with on my '08 Z06 (at least until GM comes out with the upcoming ZR1 injector). I know that Andy of A&A Corvette has used these 54# injectors successfully as of recent.
Here is some info on them:
http://www.racetronix.com/M145FM2.html
Racetronix Part # M145FM2 (Siemens FI11351)
All tests run with n-Heptane (0.6855g/mL) @ 20oC (+/-1oC), 3.0 Bar (+/-0.01 Bar) (43.5PSI) , 14VDC (+/-0.05VDC), saturated driver wtih RC cutoff. Gas (0.735g/mL) ratings converted at a 1.035:1 ratio.
Static Flow Rate @ 43.5PSI (300kPa): 46.5 lb/hr = 5.86g/s = 478cc/min (+/-3%)
Static Flow Rate @ 58.0PSI (400kPa): 53.7 lb/hr = 6.77g/s = 552cc/min (+/-3%)
Dynamic Flow Rate 2.5ms PW @ 100Hz (400kPa): 11.42mg/pulse +/-4%
Coil Resistance: 12 Ohms (This high-impedance injector will work with all factory ECM/PCM injector drivers)
Gain: 0.75
Spray Pattern: Cone
Electrical Connector: USCAR (New-style V=EV6 / Oval / LS2)
Fitted with Viton upper and lower o-rings.
Grease supplied to lubricate o-rings prior to installation.
Dynamically flowed and grouped to within 1% tolerance using Racetronix custom injector flow bench
This injector version is fitted with Viton o-rings for use in factory G.M. LS2 fuel rails and intake.
Note: Some injector flow rates have been converted from n-Heptane test solvent to 40CFR86.113, the U.S. EPA emission test gasoline. However, n-Heptane is not gasoline and flows in most common injector designs at about a 3 to 4% lower rate than 40CFR86.113, the U.S. EPA emission test gasoline.