I'm really sorry you're getting beat up in this thread. I always admired the SHO...2nd gen was my favorite. If it were mine:
I'd start using Mobil 1 EP 5W-30 in it, and if it develops any leaks, get the seals fixed. In my opinion, you've got a car worth keeping. Yeah, yeah..it's a Taurus, but how many people can claim they have a Taurus with a Yamaha 4-cam in it? In case all the naysayers here have fogotten (or never read about it), there was very high praise for that engine and for the car as a whole. The regular Taurus never got that much fanfare, but the SHO stood out as an entertaining performer to the automotive press.
I rarely see one anymore, which adds intrinsic value in my eyes. I thought they were great cars and I (and Road and Track) was sorry to see them saddle it with a V8, and then quit the project altogether.