Just installed the 7 inch trucklite from an eBay seller, about $160 delivered. Got the dynamic ringz from an Amazon seller for about $75.
Streetglide headlight has a y-cable of some sort, but the H4 plug is all you need, just remove the Y or leave it in the fairing.
Install was straightforward. No gimmicks, no "holding your mouth right" just take out the old and put in the new.
I also installed the Harley frenched or deep trim ring. Again, no proiblems encountered. It goes on over the stock trim ring. Install light, tighten bracket. Install single screw in stock trim ring loosely, remove screw in deep trim ring and slip over stock, put the crack at the bottom so you can get a small screwdriver on the stock trim ring screw, tighten, but don't Gorilla it. Push new trim ring together at the crack and insert screw and tighten till crack is flush.
Dynamic Rings go in the stock bullet turn signal housings, just insert the 1157 plug in the hold and twist. Then feed the wire in a coil behind and snap on the lens.
Turn on 4-ways, each turn signal several times and it will soon stop with the fast blink, at least mine did.
One of the easier mods I've done. About an hour, but I took my outer fairing off thinking I needed to to remove the y-cable (you don't).