There is a French company that makes replacement high precision worms in an uprated block assembly, they also make a spacer for the RA axis to allow it to track further past the meridian. The new worm gear is supposed to give +/-5 arc sec without PEC. Someone has posted a review here http://homepage.ntlworld.com/john.moore88/reports/g11_worms.htm (http://homepage.ntlworld.com/john.moore88/reports/g11_worms.htm)
A link to the Ovision product page: http://www.ovision.com/Losmandy_PresentationNS_english.html (http://www.ovision.com/Losmandy_PresentationNS_english.html)
Cheers
Robert
Thanks Robert :P