Adding a vb forum to an existing Wordpress site.
 

I've got a Wordpress site with about 10,000 avg page views a day, about 2/3 of that uniques. The site is 3 months old. Although successful (not in dollar terms though), I am tired of the daily blog posting--just too much work. My comments are active, and there is a "community" there who wants to discuss.

I'm am considering changing my site to a forum (no I don't think I could use that that bbpress, not very feature rich compared to vbulletin). But I don't want to lose all the links to the 600 pages of content I have, so I would want to keep my blog archives with the same permalinks. But then add the forum.

The blog sits in the home directly (mydomain.com/the-blog-slug). I'm trying to find out how I would add vbulletin to my site best. Would it go into mydomain.com/forum or forum.mydomain.com?

Is there any problem is the WP blog still there off the home directory, and a vbulletin forum in another directory or subdomain?

Any words of warning or advice?