Unfortunately, it's not possible to keep the URL as far as the URL structures of both forums (XenForo and wpForo) are different.
1. topic URLs
- XenForo: Site.com/threads/TOPIC_SLUG.TOPIC_ID/
- wpForo: Site.com/FORUM_SLUG/TOPIC_SLUG/
2. forum URLs
- XenForo: Site.com/forums/FORUM_SLUG.FORUM_ID/
- wpForo: Site.com/FORUM_SLUG/
However, If you contact a professional migration service, they can make 301-redirection from an old XenForo URL structure to a new wpForo URL structure. So don't lose the Google rank. I. e. the old links integrated on Google database will not return 404-page and will show the new according pages in wpForo.
In case you want to say thank you !)
We'd really appreciate and be thankful if you leave a good review on plugin page. This is the best way to say thank you to this project and support team.