[Zen Cart] Heavily modified site

[factor4]

I am considering purchasing Magic SEO, but I have a few questions first.

1. I really need SEO urls and Magic SEO looks to be the most complete solution, but I am concerned about it being able to work with my site. I have heavily modified site, which you can see at http://www.factor4weightcontrol.com. This site uses unique product types and a number of custom modifications. I am concerned that Magic SEO will not be able to rewrite all the of urls of my site, and because the source is closed, I won't be able to do anything to make it work with my customizations. Is there a solution to this?
2. Are there any drawbacks to using Magic SEO? Is mod_rewrite a search engine safe way to rewrite the urls? Is there any type of guarantee that this will help search engines index my site?
3. The whole point of SEO is keywords. Is there a way for us to customize the keywords or have any control over them? For example - our features products that are new and thus not well known, so we are going to want descriptive keywrods, such as nutritional shakes.
4. Why is it that on all of the sites I have seen with Magic SEO, the first time I click a link it appends the session id, after that it does not do it again. Not a big deal, but interesting.
5. I see that the next version (core 2) will offer enhancements and optimization. Do you have an estimate as to when this will be available?
6. How important is it to have static urls that never change? If the internal urls do change at some point, will that hurt seo?
7. I really like the way Magento uses URL Rewrites that give full control of URL's, and it has a nice interface in the admin to provide this. Does Magic SEO have anything similar, or have plans to offer a similar feature?

[inveo]

1. I don't see any reasons why Magic SEO URL will not work properly. It was developed for using on heavily modified web sites and is already running on such stores (custom Product types are supported of course).
2. mod_rewrite is the mostly used way for nice-urls. We do not provide any type of guarantee for your positions in SERPs, but we can guarantee that Magic SEO URL will be working as is claimed on our web site (you can contact our existing customers listed on Live Shop how it helped in SERPs possitions or read Testimonials).
3. No, there is no way how to customize URIs with current version.
4. Properly Sessions IDs handling - Sessions IDs (zenid parameter in URLs) are removed when one of 120 worldwide webcrawlers is detected. Also, if the webcrawler finds backward link with Session ID, it is redirected to the URL without this parameter (more in Features).
5. Summer 2008
6. I don't think that static pages are very important (crawlers are spidering dynamic URLs well now), but the most important Feature which Magic SEO URL also provides is duplicate content protection - it removes duplicate content penalization and increases PR.
7. No, it doesn't - some settings can be changed in configuration file - see Features for more details.