I saw one where the guy added a balsa face to the rudder and added a solid tail post and used CA hinges. MTK, mentioned building a new rudder at a much lighter weight also.

If you are painting it you can fill the dents, otherwise they are there for good I imagine.

There is a neat/convenient way for mounting wheel pants describedd here:
http://www.rcaerobats.net/Wayne'sWheelpants.htm

CArfs method works, used it on my Rev Pro. Im trying the above on my Impact.