Do I need bigger torsion bars?

If you are not worried about strip duty(weight transfer) I would upgrade the Tbars to something a bit more stiff for a more street friendly driver.IMHO

I would check out these threads going on now to help you out.

http://www.forabodiesonly.com/mopar/showthread.php?t=273492


cheap T-bars on the sales forum
http://www.forabodiesonly.com/mopar/showthread.php?t=261065


ps: good looking dart btw :)