I think a 4.7 will last longer all things equal. That being said both should last longer than anyone will ever need them toI’ve seen 200 series LCs for sub-$30k. Don’t be afraid of high mileage, the 5.7 is even better than the 4.7.
1st gen 21 ft, 2nd gen 19 ft.Turning radius is still about the same as an Amtrak, even with the shorter wheelbase.