you need good results and you have made a bad choice like using the dekas(630cc) go for ev14 550cc since 2871r will not max them out.In any case you can use a 4bar fpr if you need lower duty cycle on your injectors.Then next choice is 725cc which are more expensive but one of the best out there.Buy from either injector dynamics or bosch motorsport dealer.
Agreed with the others, I ran 630s on my AEB with a Comp turbo 5556 (flows between a GT 3076 and GT 3582, about 50-55 lb/hr) running about 30-35 PSI along with an adjustable FPR and never had issues going lean. So trust me, 630 Dekas can take anything that a 2871r can throw at it.
Also, as others have said, they idle well and part throttle response was never an issue. Great bang for the buck.