[jw]

It all boils down to how much HP you are looking at. There is close relationship between HP and injector size.
http://www.vfaq.com/TMO/Tuning-Tips.htm
shows you some example HP @ 80% IDC and 100% IDC. Go with what you target at.

 

[jw]

Cazzo, what is your base fuel pressure?

 

[jw]

2G base fuel is 43psi. I have read with Walbro pump, you will get around 50-60psi which is plenty rich. The stock FPR will be outrun depending on your base fuel pressure and the boost you are trying to run. Well, since you are not lean out at full boost, you have not outrun your FPR