WindowsBlinds: Updates free or not?

[CompFreak247]

Ok, so I think I'm going to get WindowsBlinds. It has a large user base, and very cool skins. I have two questions, however. First and foremost is: Once you purchase WindowsBlinds, do you automatically get the next version when it comes out for free? For example, if I buy Version 5 now, when Version 6 comes out will I:
1. Get it free as an update
2. Pay a "Upgrade Fee", smaller then the price for the full version
3. Have to buy the new version again by itself.
My second question is: Does WindowsBlinds have a significant performance hit? I heard that it simply replaces the uxtheme dll file, and as such is nearly as fast as Microsoft's default themes. I would just like to make sure, as I don't want to pay $20 for a bloated program that will slow down my none-too-fast Inspiron 1200 with 768mb of memory to a crawl.

EDIT:
Just thought of another question. After doing a little research, it appears the trial version is almost as good as the full version, and skins everything but the progress bars, scroll bars, and a few other things. However, does the trial expire? I seem to remember the last time I used the trial (which was a while ago), it expired after a certain time period.

Thanks,
-CompFreak247