I really dont know much about the Bad Boy Buggies, but from looking at a pic it looks like it is basicly an EZ-GO Workhorse 4x4 that is converted to electric, camo'ed, etc. I would bet the basic chasis and 99% of it is built by Ezgo, same company that builds golf carts. I know that you can buy heavy duty rear leaf springs and that they are usually recommended for carts with the rear seat or cargo bed, and I'd guess they are standard on the bad boy. I would also imagine you could replace those heavy duty springs with standard springs and get a better ride, but you would lose some payload capacity. Reducing tire pressure to around 5 psi would help some also.
Do like Moose said and check with the dealers, and you can also ask on a web site called buggiesunlimited.com.
No matter what you do though, its not going to ride like an independant rear suspension ATV.