Probably the best mod I made to my RG as far as rider comfort goes. The stock bars gave me a pain between the shoulder blades after an hour or two riding but these bars solved that problem completely.
Went on with no problems using all stock cables etc.
I had the dealer change my bars last May. I ended up using the plus 2 sweeper bars and did not have to change any cables. From what I recall the numbers are close to the same for the Heritage bars so you should not need to change any cables. You may wish to check the Roadglide.org forum for more info as well. I attached a couple of photos of what the sweepers looked like on the bike.