I don't have much experience with par mirrors, i fixed the poor mirror placement by getting both the HD extended mirrors and mirror extension kit. This solution gave me excellent rear view seeing. However, others may have less expensive solutions.
Regarding exhaust - i went with adding the slip on HD screamin eagle exhaust which definitely improves the sound - more of a low rumble and reasonably louder. However ,V&H slipon exhaust i hear provides a louder sound. In my case, i had to still be careful not making bike too loud as i live in a tightly packed residential area.