Yeah- OP says he has fuel pressure, but the main relay can be hard to diagnose, because the problem with the solder joints cracking can be intermittent depending on the ambient temp under the dash. My last DA developed that problem- it wouldn't start when it had been parked in the sun during the summer, until it sat with the windows open for awhile. Click here for a pretty good write-up on the relay issue, and how to fix it cheap, if you know how to solder..Definitely sounds like a problem with the main relay..
My 92 GS would not start when the engine was hot, we replaced the main relay and BAM! Problem solved and haven't had any problems since.
My 95 RS cut off on me as I was slowing down to a red light, changed the main relay and BAM! Problem solved and haven't had any problems since.