You wont notice any difference because by law the 14.5 inch barrell has the flash suppressor/compensator permenantly attatched by law. If I were you I would get a 16in barrel with a 1 in 7 twist. This gives you more options as there are some great compensators on the market that further enhance accuracy and reduce felt recoil
The process is not difficult you just have to have patience. It takes over 6 months. I am in the process of doing my second form4. I have my paper off to the state now. My next step is a can for my 300 blkout.