NSAIDS. I tried some "Vitamin I" yesterday and I could feel some small improvement in my hip (feel more like hip flexors than piriformis today). I should have been taking ibuprofen for weeks! At this point it's not going to make a dent, but I thought I'd give it a try.
I've never been this fit, the weather should be perfect (upper-30s, lower 40s, no wind), and it's a fast course. Course/conditions alone should buy me 2-3 minutes over Frederick's 3:21. On the other hand, I've never gone into a marathon with this much of an injury, so I'm apprehensive to say the least. I guess I have to have something to worry about!