First off, what engine management will you be running with the downpipe?
Second, there won't be an increase in power after adding just a fuel pump. Your FPR will still target the stock fuel pressure, which the OEM pump can do with the standard 420cc injectors. The reason you'd upgrade your fuel pump is after installing higher-flowing injectors, the stock fuel pump will not be able to hit target fuel pressure at high injector duty cycle. Adding a higher-flowing fuel pump will allow the FPR to maintain the target fuel pressure. If you are looking to produce more power (let's not talk brake horsepower here), a downpipe + tune will produce approx. 225whp. That's a 55whp increase over the stock 170whp. Adding a quality TMIC will allow you to target higher boost (less pressure drop across the core) and tune your timing more aggressively. Finally, an EWG and EL headers (with correctly matched primaries) will improve your spool and top-end, but don't expect to make over 250whp with the stock TD04-13T. With even a quality TMIC + Pro tune, you'll benefit from upgraded injectors and fuel pump. As I recall, Cobb maxes the IDCs with the OTS stage 2 map.