Looking for a new tow vehical. 18 ft bowrider I/O, steel 2 axel trailer. I figure loaded it's 4,500lbs (guess only). I've never owned a SUV (been borrowing a friends F150). It's either an Explorer, Nissan Extera (wife likes it), or a Mountaineer. Mountaineer is ALWAYS in 4wd? Pro's and cons on that? Will something wear out quicker because it's AWD while an explorer can be switched to 2wd? I tow about 2,000 miles a year. No hills. Looking new or 2-3 years old. Thanks in advance.