The Supra TT fuel pump flows 290 LPH, but its external size is actually a bit bigger than the stock pump or the Walbro unit. The Walbro unit should be a direct drop-in, but make sure you also buy the hardware that goes with the pump (electrical connector and fuel hose).
The price on the Walbro's are attractive... about $110 USD for a pump. I have had Walbro pumps on my cars, and they are proven to be very reliable and consistent IMO. My Camry also has dual in-tank Walbro pumps right now. The only downside to the Walbro's are the noise that they create....
255 LPH should support roughly 400 HP (depending on car), but 400HP is a conservative and safe estimate. A Supra TT fuel pump would support up to 500 HP with no problems.
For fuel regulator, try to look around FPR's that are for domestics (or domestic brand name). Brands such as Vortech, Mallory, Aermotive, Holley, etc... are race proven and are capable of 1000+ HP (-6AN or -8AN ports). I would stay away from lower-level brands such as Arospeed, Ractive, Tenzo, etc... because the last thing you want is some Taiwanese quality control for a part that is responsible for fuel delivery (fire hazard).
For the fuel rails, the stock ones will be more than enough for your needs. I would only consider fuel rail upgrades if I will be running 550+ cc/min injectors
