I had a vibration just like that on my Ford Probe I owned several years ago. It seemed to come from either side, just kinda from the whole front end. And found it to be coming from the CV axles. I wasn't sure if it was an inner or an outer, so I just replaced entire axle assemblies on both sides and problem cured. These Contours especially, see a lot of torque abuse on those CV joints because there is a V-6 ahead of them, and especially when torquing on them around corners, they can get a little loose in time. That's where I'd say to go (providing all those other operations you had mentioned were done correctly. Good luck finding it
'95 CONTOUR SE
-Enkei 16s
-Porsche944 Exhaust tip
-
Audi xenon projector headlights
-Peterbilt 30" air horns
-mp3 Aiwa headunit (150 songs on one disc)
-dual 10s
-soon to have LED tailights (real kind, not just gay bulbs)
-That's it for now