truggies are really there own class now, they're longer then buggies, have longer a arms so they're wider, they have different gearing, more often then not have different shock towers and radio tray as well, but truggies are a lot closer to buggies then monster trucks.

as for the center diff, with and without is like night and day, with a center diff you loose some acceleration and top speed, but you gain an enormous amount of on power cornering, which more then makes up for it, really the best truck to see the differance in is the revo and the GST, as they are the only monster trucks with the option of using a center diff, truggies have to use the CD, or have it locked which in many cases destroys the diff if you ever want to use it how it's meant to be again.