well sounds like you guys need some supra owner help. First off, The 7m blew headgaskets they didnt leak it was because the factory head bolts streched allowing it to flop around and blow. Secondly the 2jz is not the predecessor of the 7m the m series is a totaly diffrent group, The 2jz is the predecessor of the 1jz basicly its a bigger 1jz you can use the 1jz head on the 2jz block if you want which is called a 1.5jz. Third the rings did NOT leak and 55k for that car if it was babied its whole life is a lil high yes but its very much worth it.
KTHXBYE
