If you use either of them programs, then you will not have a need to lower your fps using Handbrake.
I use Handbrake to shrink the size of a video for upload when it is too large.
I have never used it to change the fps.
vegas 11 (17 videos)
vegas 12 (30 Videos)
vegas 13 (35 videos)
Near about everything that you will need in order to get up and running with Vegas.
FYI. We use an old Canon video camera to capture the sermons and special events. Initial files are in .M2T format, which Camtasia cannot handle even with the wrapper created years ago by a Techsmith employee. The initial files range in size from 6 to 14 GB. These are run through Handbrake to create an MP4 file. The MP4 files are between 1.2 and 2.8 GB. These are edited in CS8 with little or no trouble. Editing, however, is minor. Adding bible verses where mentioned or quoted. Splash page. Cut coughing attacks, drinks of water, etc. Cutting sound of short coughs, names of countries, etc. So, nothing major.
In our situation CS8 works just fine!
Oh, I failed to mention that after editing with Handbrake we had lag that kept increasing as time went on. Techsmith helpdesk, which suggested Handbrake, helped create the parameters to stop that nonsense! Occasionally, after "heavy" editing. Lag/stutter occurs around cuts and patches. Saving the project, closing CS8, reopening the project eliminates the stutter.