The 4.0 liter SOHC engine isn't one of Ford's best ideas. I'd definitely go for the V-8. I have a '97 Explorer with the 4.0 L engine, and its a dog, and only gets about 18 mpg on the highway. I've heard a lot of horror stores about the OHC engine. The 4.0 L overhead valve engine was decent, but the overhead cam version has problems with the timing chains. It may be a twin to the 2.5 Duratec for reliability problems.

-Mark- '99 Mystique LS, totally original (including the original water pump and the premium stereo)! Bought new in December 1998 for $21,000. 208,000 miles