It depends on what you want. I've owned a 93 SVX in the past, and sold it to get my 98 Legacy GT. I like both cars for different reasons. The SVX is definitely faster, but the GT feels quicker, more nimble. I think that's just because it's a 5 speed and I enjoy that more. I've got kids and wanted a 4 door, so the GT fit the bill. I got to where I was pretty worried about getting good service for my SVX. We've only got two Subaru dealerships here in Oklahoma, and the one here in town has actually shut down, and then someone else picked up the franchise. The SVX's are out of production, and I don't feel like they get continued support from Subaru like they should. I didn't want to get stuck with a car that no one could work on. It is an exotic, beautiful machine. It's great to drive, brings great pleasure, and attracts attention.
The Legacy GT is basically the same thing as the Outbacks, therefore any Subaru dealership should be well-equipped and knowledgeable to take care of the car. There is indeed quite a lot of aftermarket stuff available for the Legacy GT as well. Struts, springs, short shift kits, headers, reworked heads, cams, turbos, etc. I autocross mine, and have a blast. I've really gotten a lot of pleasure out of modifying it and making it unique. It gets quite a bit of attention as well. Here's a link to my Yahoo briefcase with some recent pictures (got new wheels!).
http://briefcase.yahoo.com/bc/richei...c=bc%26.view=l