Er...
1998MY Scorpio carries a LOT of the DEW98 platform underneath it - that's the models with black headlights instead of chrome, reprofiled bootlid, various other modifications.Scorpio was a testbed for DEW 98. It certainly shares a fair bit of Mk 3 Scorpio (which isn't very closely related to the Mk 2, but is quite closely related to the Sierra). Remember that the differences in a modern car often amount to little more than revised suspension mountings, spring rates, brake and wheel dimensions.
The 2.3 engine was specifically designed for DEW98 according to Cosworth documentation ;)
Of course, from your assumptions about them, I have to assume you've never properly driven a Scorpio. At 110mph on A7 the past Soutra Aisle (that's a bendy bit most people shy away from taking at 50), passing Saab 9-5s and caning the 16v 2.3, you realise that the '98 Scorpio's ugly face hides a very competent chassis along with the comfortable seats and generally tolerable ergonomics.
Richard