They certainly make a difference, well worth the money.
Mike you can buy a new adapter and filter thread from Honkers for $9 (including postage). I got mine from ebay seller
Link Delight, they're fast and reliable. They also have some very nice Benro stuff, I bought one of the ball heads, heaps cheaper than the Manfrotto equivalent, more features and more rigid. Be aware that the prices are quoted now in $US
If you're destitute yell out and we'll take up a collection.