@Str82u : Nope, changing post count won't create 404 errors, because the system handles it pretty nicely. The pages will redirect well.
Google says that the content hidden in page 2/3/4 won't appear in Google. So all I see is the direct traffic to the thread's first page.
Given the fact that there won't be 404 pages because of changing the post count - should I go for changing the post count?