Some newbie questions before buying

[Gazanfer]

Thank you.

I also have some php coding experience (6+ years), and modified a lot of software including phpbb and likes.

Can i mod vb on my own? I mean, let's say i wanted to add new fields that a user must enter at registration. How hard is it? Editing database and editing registration page must be easy, but integration with other mods seems like a hard job. (I tried to have a look at modification tutorials, but i can't view them since i don't have a license yet.)

Isn't there a special license of vbulletin which allows access from localhost only, so that i can test whatever i like and decide if i want vb or not? Because this site is going to be solely based on vbulletin. I don't want to buy it until i am sure that a modded vb is best solution in my case.

Also, how can i find a coder who is specialized in vb modding? i have tried service request section but i do not have the rights to post there.