yeah, that is the setup i installed on my swinger, and yes it can be very inexpensive to complete. the weight difference isn't that much, but there are aluminum calipers that would work if that was a major issue. the nice part about the caddy calipers is the integral parking brake mechanism that will work with the (in my case) stock parking brake cable with little work. the downside to these calipers is the core charge can be high and they are known to stick if you don't use the parking brake whenever you park the car. the big bitch i had was the lower caliper bolt is too close to the leaf spring. read more/see pics here:
http://www.slantsix.org/forum/viewtopic ... sc&start=0
it's all in what you want to do with your car, but IMOHO if you keep the small bolt pattern you aren't that interested in high performance anyway with limited tyre/wheel selection and either small stock drum brakes or hard to find/expensive to maintain factory disc setup, neither of which are known to work that well compared to the later large bolt stuff.
as for overkill, i have found stopping quickly is as much fun as accelerating.
-james