How do I use Get-Aduser's Filter to exclude a large number of Import-CSV user accounts ?

Hi,
A few questions here:
1. How do I build a dynamic list of users to use in the Get-Aduser -Filter from the
 $ExcludedUsers = Import-Csv $Path?  I'd like to 'exclude' these users from processing
during the Get-User operation.  Could have 2000-3000 users to exclude at any one time.
2. Is there any limit as to how many I can Filter at any one time?
3. Will the ISE Debugger still work given a large Filter statement?
#Exclude

$ExcludeOU1  = "*OU=Mailboxes,DC=MyDomain,DC=Local*"
$ExcludeOU2  = "*OU=Accounts,DC=MyDomain,DC=Local*"
$ExcludeOU3  = "*OU=USA,DC=MyDomain,DC=Local*"
$ExcludeOU4  = "*OU=OS,DC=MyDomain,DC=Local*"
$ExcludeOU5  = "*OU=C,DC=MyDomain,DC=Local*"
$ExcludeOU6  = "*OU=o,DC=MyDomain,DC=Local*"
$ExcludeOU7  = "*OU=n,DC=MyDomain,DC=Local*"
$ExcludeOU8  = "*OU=t,DC=MyDomain,DC=Local*"

$OU          = "DC=MyDomain,DC=Local"

# Import Excluded Users

$Path      = "C:\Users\Fred\ExcludedTest.Csv"
$ExcludedUsers = Import-CSV $Path

$AllUsers = Get-Aduser -Filter $ExcludedUsers -Properties mail -SearchBase $OU -SearchScope Subtree |
           ? {$_.DistinguishedName -notlike $ExcludeOU1 -and `
              $_.DistinguishedName -notlike $ExcludeOU2 -and `
              $_.DistinguishedName -notlike $ExcludeOU3 -and `
              $_.DistinguishedName -notlike $ExcludeOU4 -and `
              $_.DistinguishedName -notlike $ExcludeOU5 -and `
              $_.DistinguishedName -notlike $ExcludeOU6 -and `
              $_.DistinguishedName -notlike $ExcludeOU7 -and `
              $_.DistinguishedName -notlike $ExcludeOU8 -and `
              $_.mail -ne $null}

Thanks for your help! SdeDot