Take this for what its worth, its just my opinion based on what I have learned from talking with a few well regarded professionals, read on the internet, some magazines, a couple books, and the limited experience I have with my particular application over the last 8 months.
The '03 has a nice welded aluminum aftercooler that seems to be quite tough, and the stock intake elbow works fine. So those are unnecessary for most people that have a properly sized turbo and injectors, and easily upgraded later if you find out you need them. The elbow is, from what I can tell, a nice cosmetic upgrade and not much else. (Boost elbow fan boy with chrome strippers on his back window and 24" rockstars commenting in 5,4,3,2....)