Does anyone know of any Japanese sites similar to NewEgg (http://www.newegg.com) that sells computer parts, and customers can write reviews on them? I'm not looking to actually buy anything, so it doesn't matter to me if there are shipping restrictions.

I'm assuming that you want to use the site as practice for talk about computer/tech issues. If this is what you're looking for, then the closest thing is probably 価格.com (kakaku.com), which is actually a price-comparison search engine (similar to pricematch.com). They have more than just computer stuff -- almost anything, actually. Users of the site can post comments about each product, and it's very common to see people debating the merits/drawbacks of one item over another, as well as asking basic technical questions relating to compatibility, etc...

If you're looking to use the site as a study tool, do a search for an item you're interested in (i.e. SAS RAID コントローラ) and pick one of the products that come up. There will be a comments section called "クチコミ" that you can click on to see everyone's comments.

Thank you so much! This is exactly what I was looking for