A VLSD is not locked at all times. Does not lock on decel. When you drift your entrys would be less pronounced and your exits would be more controllable, but would have less angle. With a welded you would have full lock, all the time. More pronounced entrys, more angle, also a tad more to handle if you dont have any throttle control cause it's easier to oversteer. This is a simple breakdown though, we could talk about this for hours and still get no where. Me personally I love VLSD. I wouldn't rock one if I had 300 hp and coilovers and all but for a mild 240 thats daily driven, VLSD cant be beat.