There is something said about the different lengths of the spark plug cables playing a part with firing or something. Can't really remember what it was since I didn't think I would have done what you did but does it run any different?
So, where is your horn now? I've seen some with it in between the downtubes.
That coil is gonna get a tad bit hotter in that location. Also like was said earlier the shorter wires will advance you timing so you should retard it a little or it may fire too early causing damage especially when its hot
as long as the resistance in ohms is between 5K and 11,666 there should not be a problem. I also doubt there will be much heat difference between that and stock location as it is in the air flow.
I moved the horn to where the coil was,best part is I didnt have to change any wiring except for the spark plug wires. I havent noticed any difference in how it runs. The thing that cost the most was the chrome coil cover,its not after market it is oem for Dyna models so it was $75 ,spark plug wires were $36 and the bracket I made myself.