42021FA032 (the original one was 030 and then 031 and the current one is 032). The only problem is that this part is $290 USD.
This is a common part to North America but I don't know for which vehicles (it doesn't show).
A better choice is probably the Walbro GSS342-400-791 255lph fuel pump which you can easily find for ~$100 USD and is a nice upgrade especially for any future mods and increase boost etc..WRXTC used a GSS342 in his EJ20G with good results but I don't know the exact model# but the one I mentioned is said to be compatible with all WRX/STi.