The install can range from extremely simple to mildly complex depending on the car. The biggest constraint is space getting your hand to the bulbs. For my '16 Mazda6 i was able to install both the DRL/High Beams and the Low beams without removing the front bumper. The rest of the install is self explanatory. Follow the install guide and it will let you know whether you need the polarity switches / capacitors as well.
The install was quite easy on the Mazda 6. Might need the use of some small hands. I didn't take ANYTHING apart. Just reached in and snagged the old out and put the new in. They are hella bright.
How is the light quality (i.e., beam spread, cutoff, consistency of lighting, etc.) with the OPT 7s? I was looking at these the other day, but all of the research I've don on HID and LED retrofits suggest LED bulbs are a downgrade in stock projector housings.
IMO stay away from Opt7. They are not really a name brand but rather cheap Chinese made bulbs with fancy packaging. My wife has Opt7 led headlights on her car and while the output is ok, not better or worse than the stock halogens. Yeah the are "hella bright" but only when looking directly at them or driving behind someone with them. The problem is that the beam spread is all over the place and they are blinding to other drivers but they don't project down the road better than the stock halogens and definitively nowhere near HID's. I had to angle her headlights down to negate that blinding effect. The other problem is that they are 6000k which "look cool" but they produce a lot of useless light. 5000k would be the max I'd go for LED headlights or even HID's. I'm currently looking into XKGLOW LED headlights as they have a dedicated cutoff and more usable light. I still need to do more research but I can tell you that Opt7 is old LED tech and there is MUCH better out there.