joe...I think in your case, I'd go with a unit similar to what you had. It's possible, if you branch supply ducts off your existing system, you could upset the entire delivery balance of the home. You'd certainly be heating the basement 24/7 unless you want to manually open and close the supplies according to use. That could require a whole house load balance each time you open or close the registers to maintain upstairs comfort levels. I think you get the idea.