E-commerce site doubling its product pages: is that going to be a shock for SEO?

[fabrizio]

Hello here,
I own an e-commerce website and in a few days we are going to include additional 100,000 products to our catalog. That means 100,000 more product pages potentially to be indexed by Google.

My question is: is that going to have a "positive" or a "negative" effect for our SEO? Do you think that would be better to release and allow Google to index that amount of pages gradually, or that doesn't matter? And what about the sitemaps that would increase right away of additional 100,000 items?

I would really like to know your thoughts about this important issue, I am just worried about possible "side effects" such as PR dilution or a drastic change of our SE positioning among our well ranked pages.

Any ideas and thoughts are very welcome!

Thank you in advance.

Best,
Fabrizio Ferrari, CEO
Virtual Sheet Music, Inc.
Classical Sheet Music Downloads