I have them in my duster and it really stiffens the chassis up, this is a no brainer mod.
MP sells bolt on ones from summit, they did require minor grinding to fit, installation is easy.
Did you see the two reviews? One guy said they were total junk and got stuck with them for $200 ! LOL and the one guy that gave him five stars ended up having to weld them in anyways LOL what a joke!!