I asked my dealer about the clunk and he informed me of this solution. He said he tried it on a 2001 Cobra with a clunk and it only worked for a short time. Sorry to break you the bad news.
how long did it take for the clunk to be present? i just picked mine up monday and it has 155 miles with no clunk present.and mine shifts smooth as silk not like the clunky 6 speed that my 94 firehawk had.