I am running a very similar set-up. The SE-Pro Stage VI did not have a trottlebody compatible with the electronic throttle on the 2012's, so I did the SE Pro Stage III and added the Factory CNC Ported heads with the head exchange program. So, the biuld included the 10.5:1 Pistons, SERT, 259E Cams and the CNC Heads. It was installed before I took delivery, so the dealer is covering under the manufacturers warranty I have not had it dyno'ed yet, but it pulls great and has plenty of passing strength at highway speeds. I love it. I am concerned about long term reliability, but I paln on purchasing the extended warranty. I can tell you the gas mileage is less than stock, but what do you expect if your are installing race parts.
I believe the main difference between the race kit and the street legal kit is the SE Tuner. They porbably just have a download with the street legal one.
2012 FLHX - Vivid Black, SE Stage IV 103 w/ SE 259E Cams, SE Heavy Breather, Vance and Hines Power Duals w/ Hi-output Slip-ons, Progressive Mono-tube Front Susp., HD Premium Rear Shocks, Boom Audio speakers, etc....