I recently aquired an '05 intake manifold with the fuel rails and injectors and I will be modifiying it to fit on my '00 RS. With that in mind, this thread will be a source of info for others wanting to do the same and hopefully some people here can help with questions I might have. Here is a quote from Steve Sulatycki someone posted on the rs25 forums on what needs to be changed:
"For 00 -> 05, you'll need to change:
- Coilpack and spark plug wires
- Fuel rail (all components)
- Fuel injectors - they are now "WRX" style and stock WRX units work well
- Drill holes for the '00 TB - bolt pattern is different
- Drill a hole/boss to mount in the MAP/IAC sensor onto the manifold. The
05+ are MAF based and as such there is nowhere to bolt the MAP onto.
- Port match the intake runners to the '00 intake ports. The ID of the
runners on the 05+ manifold are larger and the misalignment that results
has to be dealt with
- Relocate/mount the throttle cable to the manifold. All 05+ are
electronic TBs and there no existing mount for the throttle cable."
Here are a couple pictures of the manifold I have that I'll be working on: