Tubular Lower Control Arm Thread

Educate me, what is the problem with torsion bars?
For me it is a # of things, mainly its the extra room for my custom headers,exhaust and the simplicity of tranny, starter Re, and Re, for my racing clutch,as well as going two front steer just opens up the hole area for rear sump and kick out oil pan ect. Very little of it was to do with the suspension gains other than weight loss.