Sounds a tad tight to me. You should really build in the possibility of a delay to the arrival of you flight into KUL. Since your onward connection is not an interline one but an entirely seperate contract you would have to rebook and pay again (probably a much higher fare). I know it's a pain having to hang around between flights but if I plan a connection between a legacy and an LCC I tend to give myself plenty of buffer time (minimum 4-5 hours). Even that is of course no guarantee.