SERPS, Link Wheels & Micro-Niche ?s from a Newbie...

I'm trying to figure out, from a SEO perspective, the best set up for my "multi-topic within a niche" ecommerce shop. Initially I was going to lump all the topics under one umbrella domain separating categories only. But from reading about silo structures, micro niches and link wheels I'm not sure that would be the best way to go in regards to ranking well within the SERPS.

I've reconsidered that I should possibly configure my site as follows....

In the end I'll have a central niche/domain with 5 micro-niche/subdomains.

Using WP I create 6 blogs... 1 as the central niche/domain is actually an ecommerce site/blog with 5 main product categories.

• racecars.com/ferraris
• racecars.com/yugos
• etc.

The other 5 blogs are set up with a micro-niche structure as subdomain and have support/interesting/"presell" articles to link to the central ecommerce product pages. These 5 are the blogs I'm trying to get ranked well within the SERPS by specifically targeting keywords as subdomains and strengthening/supporting them with long tail keywords as article titles.

--daytona.racecars.com as a subdomain with long tail keyword article titles

• daytona.racecars.com/how-to-qualify-as-a-pro-racecar-driver
• dayton.racecars.com/top-10-racing schools

--illegal-racing.racecars.com as a subdomain with long tail keyword article titles

• illegal-racing.racecars.com/how-not-to-get-caught-racing-on-city-streets
• illegal-racing.racecars.com/how-to-supe-up-a-junk-engine

Question 1: Am I understanding this premise correctly? Since Google will regard these as different domains this helps the subdomains rank better if a targeted keyword is the subdomain name? Or is that just silly talk?

Question 2: Will Google consider 6 blogs as too many blogs on 1 ip?

The micro-niche/subdomain blogs will not interlink to one another to form a link-wheel per se. Rather the articles will point to the central niche/domain products (or affiliate products if better suited).

• illegal-racing.racecars.com/how-not-to-get-caught-racing-on-city-streets

is an article on how to supe up a yugo as a deceptively super fast racecar & links to the shop category of fluctuating products called...

• racecars.com/yugos/deceive-everyone-kits

From a visitor perspective I was going to duplicate the template & header and interconnect each blog so that it looks as though it's all one. The sidebar content will change according to subdomain specifics, however.

I'll also use the same database for login so visitors only need to have one login & password.

Thanks for any help/advice,

Rashell