OK, good to know. My brain seems to have lost all knowledge of the 'e' modifier. Tried to get it to work with this simple example:

my $new = 'blah';
my $string = 'asdfjkjl';
my $find = '(asd)';
my $replace = '$1' . $new;

replace ($string, $find, $replace);

sub replace {
  my $string = shift;
  my $left = shift;
  my $replace = shift;
  $string =~ s/$left/$replace/e;
  print $string;
}
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Still prints $1 in the output though. Adding 'ee' throws an error: "Bareword found where operator expected at (eval 1) line 1, near "$1blah"