After testing the MaxDownloadSize and MaxGrowFactor registry entries, I have something important to share: SharePoint 2010's Search registry settings are not universally able to be modified in the registry directly.
In this case, if you directly edit MaxDownloadSize and/or MaxGrowFactor for the Crawl Component in the registry branch (HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office Server\12.0\Search\Applications\<guid>-crawl-<#>\Gathering Manager) and then restart OSearch14, the setting will simply be overwritten and restored back to its default setting of 16 and 4, respectively.
To fix this, you need to do the following in the SharePoint 2010 PowerShell console:
1. Get the Search Service Application and store it in a variable by running:
$ssa = Get-SPEnterpriseSearchServiceApplication
2. To get the current value of the MaxDownloadSize in the MSSConfiguration table:
3. The same thing can be done for "MaxGrowFactor" - $SSA.GetProperty("MaxGrowFactor")
4. To modify the MaxDownloadSize and MaxGrowFactor values (assuming the customer wants or needs to adjust MaxGrowFactor):
$SSA.SetProperty(“MaxDownloadSize”, <size bigger than 16 for what you want to crawl>)
$SSA.SetProperty("MaxGrowFactor", <size bigger than 4>)
Once this is done, you can safely restart OSearch14 and, at that time, the larger files will be able to be crawled without further problems.