Using php mail() to do simple checks - email

Question

I am using php mail() (Via piped to program) and my goal is to simply get the email and scan the "from" header to filter it and then if it passes my "rules" or "checks" pass it along to the intended receiver. I have been able to use a sample code to get the mail and I can actually get my "test check" done. The problem I am having is that I cannot get the php mail() function to resend the mail as it was (plain or html). Every time i get my test mail, it comes with all the headers exposed and code. Not a nice and neat email. I also found out that I could encounter problems with this if there are attachments to the mail. I have seen alot of suggestions about going thru PHPMailer and I am willing to entertain that option. I just don't need this to get to complicated. here is the code I am using -
#!/usr/bin/php -q
<?php
$notify= 'myemail#mydomain.com'; // an email address required in case of errors
function mailRead($iKlimit = "")
{
if ($iKlimit == "") {
$iKlimit = 1024;
}
$sErrorSTDINFail = "Error - failed to read mail from STDIN!";
$fp = fopen("php://stdin", "r");
if (!$fp) {
echo $sErrorSTDINFail;
exit();
}
$sEmail = "";
if ($iKlimit == -1) {
while (!feof($fp)) {
$sEmail .= fread($fp, 1024);
}
} else {
while (!feof($fp) && $i_limit < $iKlimit) {
$sEmail .= fread($fp, 1024);
$i_limit++;
}
}
fclose($fp);
return $sEmail;
}
$email = mailRead();
$lines = explode("\n", $email);
$to = "";
$from = "";
$subject = "";
$headers = "";
$message = "";
$splittingheaders = true;
for ($i=0; $i < count($lines); $i++) {
if ($splittingheaders) {
$headers .= $lines[$i]."\n";
if (preg_match("/^Subject: (.*)/", $lines[$i], $matches)) {
$subject = $matches[1];
}
$tst = substr($subject, -3);
if ($tst == "win" | $tst == "biz" | $tst == "net"){
$subject = $subject . "BAD ADDRESS";
}
if (preg_match("/^From: (.*)/", $lines[$i], $matches)) {
$from = $matches[1];
}
if (preg_match("/^To: (.*)/", $lines[$i], $matches)) {
$to = $matches[1];
}
} else {
// not a header, but message
$message .= $lines[$i]."\n";
}
if (trim($lines[$i])=="") {
// empty line, header section has ended
$splittingheaders = false;
}
}
mail('noreply#mydomain.com', $subject, $message);
?>
I am interested in learning, I am code savvy. Somewhat new to email formatting, but very understanding of PHP. Any help is appreciated. Thanx.