From what forum software did you convert to vBulletin to?
vBulletin 3.8.4 PL1

How big is the database in file size? (compressed/uncompressed, database or flatfile)
DB uncompressed = +150MB

How many registered members?
+180

How many threads?
+1,800

How many posts?
+27,000 million

How many attachments? (total and file size)
None

And do you remember how long it took you to do the actual convert?
about 30 minutes to {

get the .sql, import into new db,
upload 3.8.4pl1 and run upgrade.php
download impex 1.93 and upload to target site
backup target site
setup impexconfig.php
run impex
run update counters
}

it all went smooth and fast,

1 problem: polls show up on the wrong thread.