that would be me :) I think you could do even better performaning things than this with plain bzip2/gz.
Look: I don't care how you format attachments, whether uuencode or MIME, but a significant number of people on this list do not wish to receive attachments, or are prohibited from receiving them by their mail server admins. This is not a rule we have come to without any debate or for no reason and it's a fairly simple one: NO ATTACHMENTS. Put the file on the web somewhere and send the list the URL. They screw the digest version up and get error messages sent to the list admins. Please don't do it.
As a corollary, I will be telephoning at least one organisation on Monday morning to ask them to correct their mail server misconfiguation *and* add the postmaster address before I talk to their uplink. All email addresses subscribed to this list must have a working postmaster at their top level. I don't think that's a common problem, as this is only the second I have encountered. linuxfreemail was the first, and they're banned not fixed, so avoid them if you want webmail for this list ;-)
Yep, I've got the stompy boots on today. I didn't think anyone still used uuencode attachments :-(