I hope that even though this is a DIY question ...."that anyone can do that has even half the ability", that this thread won't get canned and we HO's can get some good information from all the Pros here.
I'm sure most of the HO's that come on this site are more than just the common person anyway.
What's the best way to seal up the duct system?
How can you tell you have everything sealed properly?
I'm sure something as simple as this can make any sysytem work better at the least. Most of the common people like me own a home with a system that was installed by less than "preffered" installation "professionals".
We need things to look for on solid duct systems and flex systems to help improvements.