i think with the marking thing it all depends on the dog and luck
my scampi and sasha decided that they wanted a family (without asking me first) lol
and scampi was no different after, he never marked b4 or after, and he was still a really good boy in everyway. as for pimping your dog lol trust me its not like your going to make him do anything he doesnt want to do lol
if you think he would be a good stud dog and all the health checks are done then i see no problem with doing it and just keep your fingers crossed that he stays the same after as some do change.