Those that like 02-03 front end... Buy 04 sti and take it to a body shop for front end swap.
Cost depends on how far you want to go and how "proper" you want it.
Also if staying stock brakes, leave abs alone... Easier to send out wiring and have it merged.
Dbw gas pedal bracket not needed, you can bolt on with one bolt ( not recommended)
Rs trans is push style and wrx/sti is pull style clutch.
5x114.3 is only different on the front strut bottom piece (5x100 unit can be drilled out to work or swap collar)
Another option is... Sell your car and use that money + swap money and buy swapped car for cheap.
Swap is not difficult to do. I did mine myself years ago with minimum mechanical experience.
P.s. rs isn't as light as you think.