Heck, just buy two like many of us here, the reliability of 2 svxs is nearly 100%
Some parts are prohibitively expensive (1200 windsheild, for example). Make sure the 92 you are looking at has had the transmission updated (repaired by subaru post 94).
If the transmission has not been updated, it WILL fail, either in the clutch packs, or the front diff (they seem to be grenading lately on the older SVXii) While the front diff was not changed from earlier cars, the newer it is, it seems, the better.
I think it is worthwhile for everyone looking at an SVX with over 100k miles on the clock to add the following the purchase price immediately.
New knock sensors
New 02s
new vacuum lines under the intake plenum
timing belt service
There will be those who disagree with me, but doing that to the car up front will give you tens of thousands of miles of reliability, fuel economy, and peace of mind.
Other things to check (that haven't already been mentioned, good suggestions, all of them)
The plastic window guides tend to fail in the front windows, causing scratches in the glass on both front driver and passenger sides.
Make sure the AWD is functional, the solenoid that governs rear wheel activity tends to fail on higher mileage trannys (duty sol. C).
Make sure the steering rack isn't leaking, and that the tie rods are in good condition (bear of a job)
The sunvisors droop.
2 or all of the wheels are probably on backwards
Rust and or water in the trunk.
Condensation in the tail lights.
All in all, keep this in mind, the SVX was essentially a concept car that went to production, the motor was one off (and probably the best ever made by subaru) the platform wasn't shared with other cars, the transmission wasn't intended to be geared as high as it is. The brakes aren't as heavy duty as they should have been, the sunvisors weren't intended to be covered with velor.
On the plus side, its a nicer ride than anything else at this price (some say at any price) and one of the best looking cars on the road. It is unbeatable in the snow, holds a .9g on the skidpad. It can go 150. And built into every SVX purchase is an unbeatable base of knowledge and friendship on this forum.
-Patrick