Sounds to me like you want a modern car disguised as a truck. My suggestion is to get a running truck and drive it as is a while then decide if you want to change it to a car disguised as a truck.
I agree disc brakes and a dual MC and seat belts are great improvements to the old trucks but I don't see the need for the suspension changes and other "comfort" mods.
Check out the HiPo forum for discussions of the mods you are asking about.
