How difficult is an Impex conversion
 

Ok* I think I'm finally going to bite the bullet and do this:

I have a phpbb 2.x.xx forum with 15*000 members and 3/4 million posts* 7 years old which I intend to convert to vbulletin.

I can install a vbulletin forum without any problem. However* I'm not at all familiar with databases (other than creating a new one via my hosting cpanel) or with phpmyadmin etc. I dont know much about how the Impex conversion actually works or whether my server has sufficient resources with such a large database to convert - anticipating dreaded timeouts half way through.

Is this something I should even be attempting with my level of knowledge or will it all end in tears?