I ask you, how?
Good job, but it's a little overkill. First, I have the legacy postbit setting set to '0' in the settings. I make a profile field giving the user this option, and in my phpinclude_start template, I add an if statement to check the value of the profile field, and if it is set to the vB2 style, set $vboptions['legacypostibt'] to '1'.
No hacking required, no unneeded queries, just a simple template mod.
Nice work, but it's just overkill to do 9 file edits when none are needed.