That's something I'd like to hear from some official source. Mustaine got kicked from Metallica because of some personal things (well, it was said the reason was alcohol, but if you really got kicked from the 80s Metallica because of alcohol, you must have bathed in it) and there are some Metallica parodies in some of Megadeth's songs. Listen to "go to hell" for example, released at least on Hidden Treasures. There's also a lot of similarities with some of their songs. It's understandable that their old (Kill 'em All and Ride the Lightning) have influenced many Megadeth's songs, after all Mustaine played on KEA and probably trained with Metallica playing RTL songs. Anyways what I know, Mustaine seems to be "worshipping" Metallica and Lars&James have hit him down time after time. Anyways Metallica has gone so commercial now that I can imagine a title "Old Grudges gone, Mustaine with Metallca after tens of years" at news papers. personaly id love to see it happen im a metallica and megadeth fan.