Well I was wrong again. The tubes being swapped out are the 6H30 after all. OneObgin has posted more info m on his vertual system thread. Cost appears to be $59 for parts only, plus any transportation. OneObgin confirms improved bass and treble behavior after the update. Please see the few posts relating to this subject starting at::
http://forum.audiogon.com/cgi-bin/fr.pl?vaslt&1049587927&openfrom&162&4#162
http://forum.audiogon.com/cgi-bin/fr.pl?vaslt&1049587927&openfrom&162&4#162