I was curious: lets say a website exists, and it features tons of sub-sub-pages (IE: reviews of different models of cars) First: Will linking to these sub-pages (yoursite.com/honda/X34LA-ModelName.html) from your home-page using anchor text (just like a backlink, but on your own site) do anything for you? Or would it actually do harm? Also what about linking to a bunch of sub-pages from your index with exact anchor tags (IE: exact Model number and name) - and lets say you end up with 40 links on the home-page with exact anchor text linking to sub-pages. Essentially will this harm or do good, or just do nothing?
it can not harm only do good. your homepage in most cases is the most ranked page of your website and google will look at this in a good way...
Yes linking is very good technique to promote website's internal pages but it will be harm in only PR distribution case expect of this no harm to internal linking. Page rank is not important than targeting keywords.
Yes, anchor text helps a lot in creating a good internal linking structure. But excessive internal linking is definitely bad. It won’t give you any benefit for keyword ranking. So, focus on creating good structure.