I owned a 2009 JCW for the last 2.5 years prior to getting my 2009 135 m sport 6 speed. I would say the jcw is significantly more direct and less isolated from the road than the 135. If you had driven the jcw recently before driving the 135 it may make the 135 feel softer than it normally does.
For better or worse the JCW is frenetic little car. I loved mine but, it does have it's drawbacks. Hence, my 135.
2009 BMW Black Sapphire 135i M Sport - bone stock.....for now.