I don't understand why somebody would want to turbocharge a 2002 RS. The WRX is available in that body style, so why not use what's available? Aside from a engine prepped from the factory for a turbo, the suspension is better, the brakes are better, some interior pieces are better. It just doesn't make sense to try and do what Subaru has already done for you.
On a GC8, however, there is no factory option, so aftermarket turbos are obviously the way to go.
Regarding your question, though, if you really want a turbo, make sure you thuroughly read the aftermarket turbo section of this site. The problems that some of those guys are having and the thousands upon thousands of dollars they are spending is enough to make anybody think twice.
At this point, I think the only way I'll go forced induction is if a decent SC kit comes out. Otherwise I'll play it safe in the world of N/A.