Hi John I have fitted a few of Marty's shock now. They do come with instructions and they are quite easy to follow. Standard rear shocks, if you messure from the ridge on the shock where the lower coil spring cone fits to the centre of the lower shock bush is 5.5 inches, aprox 140mm. If you want to lower the rear set up by say 1 inch then the new collar is 4.5 inches aprox 115mm up from the centre of the lower bush. Marty says most owners lower theirs by this one inch. I have on all the ones I fitted. Mark [Non-text portions of this message have been removed] DOC UK Website: www.deloreans.co.uk Unsubscribe: doc-uk-unsubscribe@xxxxxxxxxxxxxxx ** Unless otherwise stated, all messages posted to the group are assumed public and may be printed in the club magazine ** Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/doc-uk/ <*> To unsubscribe from this group, send an email to: doc-uk-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/