Personally I think that whole "sagging" thing is a myth. If its a rotten POS, yeah, it'll probably sag. Otherwise, I seriously have my doubts. But, hey, do it whichever way you feel confident. Have fun welding those in in the 10" space between the shop floor and the floor pan !!
Maybe not sagging, but try to jack a car up by one corner! The car will flex to where you can't get the doors open!
The ride of my '63 Dodge was substantially different after just having subframe connectors installed! I also noticed a difference with the recent 6 point rollbar addition.
