gonna be selling my 95 3500 soon and am going to get a newer truck and need some advice as what to get, I'll have about $21,000. to spend, I definetly want a 5 or 6 speed manual and a dually, should I get a 12v'er or 24v'er? any year I should stay away from? I'm going to be upgrading my 31' Jayco to a 5th wheel soon so I guess I'll stick to a 2wd so the bed won't be to high. any suggestions?