Looks. With large enough injectors, the amout of fuel that can flow through the rail becomes and issue but typically, stock is fine for all but the most powerful engines. Type R fuel pump is the same basic thing. I haven't actually seen any concrete data that supports any of the Integra fuel pumps flowing any better than the factory Civic stuff (my B18C1 ran fine in a '92 CX with a stock pump). It's typically worthwhie to replace/upgrade the pump on a turbo application where the engine is injesting a lot more fuel and could overwealm the pump or if your stock piece is simply old enough to that your worried about it failing.