Add unique title meta into each page in case
of large number of pages, you should be able to add
them dynamically by replacing product name, category etc)
Add unique page name without query string meaningful name
add content into respective pages
It allows user to generate sitemap.xml, google analytics and other tracking script insertion and if require, you can also generate Google FEED .
These are some basic and important requirements.
If you think you can handle these, go with customized CMS.
The impact of keywords in the URL is not as important as
you think. Ensuring that your targeted terms are in the page
title, content and headings, internal and external backlink
anchor text etc are all much more powerful signals.
You can change your title frequently, but each time the
spiders visit your site, your ranking will be updated.
Try to invest in your link popularity and your content.
You can only get better ranking on more and more
keywords if you do things right
Don't confuse "exact match domains" with exact match URLs.