To be honest , ANYTHING longer would be better !
Best bang for the buck (bar NONE) is stock OEM factory headers and heatshields with "good" proven slip-on mufflers
I am hoping you got the original exhaust setup with the bike ? If not a Fatboy system will bolt right up.
Mufflers to choose from , Khromewerks 3.5" HP OR S&S slip ons ( but they are embossed S&S which some don't like !)
Rush Racing are good also. Your Springer would have had "slash down" type mufflers as stock , so Rush and Khrome werks and S&S all make a "lookalike".
I have used all three brands in the past for me and I have put them on many mate's bikes over the years.
My personal preference , Khromewerks.
That said my own 2008 CVO Springer has a complete V&H system , that was on it in Texas in 2011 ( before I brought it to Perth Western Australia !)
Reason it is still on ? I was not going to spend over a grand $Aussie to "fix" them. It is a Big Shot Staggered system , longer than yours and with a V&H "power chamber".
This is as it happens a V&H system that actually "works".
Your current Short Shots are indeed a true dual setup , harder to tune.
I spent some time gathering up all the parts to "make" a stock OEM exhaust for mine , including stock US non cat slash down mufflers.
Hanging oiled up in the shed for "the future"..