As Neverdone and Seattlejester indicated there are pros and cons to each setup. I went with an external system. It has been working without issue for 4+ years in my RB25DET/S30. There is enough room back there to mount everything and I used the existing factory wiring (hot Green wire and Black chassis ground). Both the low pressure supply clicker style pump and the Walbro EFI pump work great and don't get hot. I have never had the fuel cut in a corner (street use only). The Walbro fuel pump whines under normal operating conditions. My understanding is that the Bosch is more expensive and quieter, spend the money. I am using the small BC Broncos swirl pot which doubles as a filter.
Internal pumps are industry standard because the fuel cools the pump, but you must modify your tank. No problem if you know how to modify a thin steel tank, go for it (and many people on this site have those skills), but imagining you will find someone or a shop to modify your fuel tank maybe wishful thinking.
Regardless you must have a properly sized return line to keep everything in balance. I replaced the 1/4-inch line with a 5/16ths and used the upper 3/8ths vent port on the tank to return the fuel. TonyD points out you can use the fuel vent line (5/16ths or 3/8ths) as your return that runs from the from the back near the tank to the engine bay, as long as you are willing to reconfigure your fuel vapor system after that.