Here is what Dan Cragin at DC performance and others have to say about long term results.
http://vca2.viperclub.org/forums/showflat.php?Cat=&Board=UBB21&Number=476459&page=0&view=collapsed&sb=5&o=&fpart=1
http://vca2.viperclub.org/forums/showflat.php?Cat=&Board=UBB21&Number=476459&page=0&view=collapsed&sb=5&o=&fpart=1