My Opinion: At $1000 for the whole Rinehart system, you can definitely save money with the Fullsac. Personally, I don't care for the look of the header pipe on the Rinehart TD...kinda defeats the purpose of having TD's on the bike to have the rear pipe still on the right side. I can't speak to the noise level, but listened to a Utube video of the RH and they seem a bit loud for my tastes. I have not seen a Dyno chart to compare the two, but if history holds true, with TD's you gnerally lose some on the low end and gain it on the high end (TQ/HP). So, with the RH system, SERT, and Dyno time, he's going to have at least $1600 in it, not counting labor if he is having the dealer install the pipes.
Fullsac Xpipe, 1.75" cores for mufflers, and TTS Mastertune w/necessary cables to "talk" to the ECM...< $1100 for the parts, and TTS map from Fullsac, which, IMO, eliminates the need for Dyno time. Install is easy, maintains the stock look, reduces the heat (eliminates the Cat), runs strong, sounds good. If you have ANY mechanical ability, and a laptop computer, you can do it all yourself. If not, any independent shop could do this, or talk to Steve at Fullsac and see if there is someone local that he can recommend to do the work. Of course, I like the look of the stock mufflers, so all bets are off if he doesn't. With the Fullsac, you reuse the stock muffler cans and all heat shields...everything fits perfectly.
I did this to my SERGU, with the 2" cores, and couldn't be happier with the results. Barks a little when I want it to, but not loud at cruising speeds. The 1.75" cores would be slightly quieter, but still sound "like a Harley". A LOT of folks are running this system with excellent results.
Yes, V&H does make a set of true duals for current baggers, but again, they are going to be in the same price range as the RH's, at least.