Does Anybody know absolute or relative cost of forzed parameterization in SQL Server 2008?
I'm not aware of anything put out by Ms more than the guidelines from Forced Parameterization. If my opinion is of any value, from what i know about this process, the cost of changing the plan to be forced parametrized has a minimal impact on the overal cost of the query. As always, there are always a lot more details that can push the answer into the realms of 'it depends', like: complexitiy of the query, possible impact of parameter sniffing, posible loss of partition restrctions etc etc, but you asked a very generic question.
You can read my reply at http://stackoverflow.com/questions/1608522/dynamically-created-sql-vs-parameters-in-sql-server/1608856#1608856 on an more detailed explanation on a related topic, why simple/forced parametrization is a far cry from actually using true parameterized queries.