The XTX doesn't have 1/2in LP ports for the primary 2nd stage and also you can left hand rig the 2nd stages if you desire
the XTX 40 rigs I think still used the DS4 first stage (could be wrong on this), I'd second the XTX40 with a DIN fitting
have a look on the ads here for second hand BC's, there's no point lashing out huge amounts on one as they are only a glorified tank holder
