Hi, i would like to see the actual installation but my first reaction is that without the bumpstops you are bottoming out the dampers and damaging the internals. The 1303 does have soft TBs and their movement needs to be catered for. Are you sure that the Left damper is not solid when you drive it?
You should be able to get some universal bumpstops that fit over the top of the damper rod that would then put the bump stop exactly where its needed. Those polyurethane bumpstops are available from various EU suppliers of motorsport bits. For example,
http://www.superflex.co.uk/proddetai...od=SF391-1833K
Clive