I have a 2004 Explorer XLT, and take it off road.  It handles better off-road than my 1999 XLT Ranger Off-Road package ever did.   Engines if ragged on, will fail.  Common snese should tell you that.  
Once I hit 15,000 miles I will be putting AMSOIL in the 4.0L.  We're buying this after the lease is up.
Karaya