optimizing stored procedure performance using CTEs

Hi - There is a stored procedure, that has parameters, which is in need of performance improvement.  I plan to rewrite it using CTEs rather than temp tables which is how it is now.  From a performance perspective, it is best to incorporate WHERE clauses in the CTEs that filter rows based on the parameter settings rather than do all of the filtering in the outer SELECT statement that references the CTEs?

For example:

--all filtering at end
select
a.Field1
from TableA a
inner join TableB b
on a.Field1 = b.Field1
where a.Field2 = @Parameter;

--filtering in CTE
with
CTE as
(
 select
 Field1
 from TableA
 where Field2 = @Parameter
)
select
a.Field1
from CTE a
inner join TableB b
on a.Field1 = b.Field1;