Torsion Bar rear suspension with Coil Springs question.

How hard is it to get down low on this type of rear setup?  I'm thinking about a van that has this set up in the rear and just wondering how extensive the work has to be to get it down low and also if this style of suspension prohibits any type of excessive camber. If anyone is wondering i'm looking pretty hard at the 2011 Siena and its rear setup will probably be "torsion beam rear suspension with coil springs and gas-filled shock absorbers"  Any info guys?  I'm pretty sure it's suspension isn't far off from the current model Estima.  I'm wanting bags or air struts but I dunno how a set up like that would work on the torsion bar sus.

its the same as a VW or my Honda stepwgn
you will be ale to go pretty low
but you may haev to haev arms custom made to correct toe

aight thanks again.