[DarkPira7e]

Azure is spot on. I think the build was a little ambitious for the power goals and the more you touch, the more you are rolling the dice.
I can't comment on lightweight pulleys, but I have a Fluidampr on mine and rev to 8k, no weirdness.

No telling where the misfires came from, it could be vibrations causing issues but I'm not going to blame something on a concept I don't understand well enough.
Definitely replace the cam gears. There's so much on the internals of those that can hold debris. The internal flaps the control engagement can become loose or go bad (I had a couple like this., No symptoms when my 3rd recall failure engine replacement spun a bearing, but it would've caused issues later)
After my rebuild, we had a noise like this. The dowel on the cam was loose. A cam sprocket had a loose bolt and it slipped on the cam, causing a super loud bang noise. We had no idea what it was until we took the timing cover off and removed the cam gear to replace all 4 of them like I should have done initially..

Did you get a new timing cover? If I could give anyone who is undertaking a build like this advice, it would be to replace the timing cover, and ALL cam sprockets on a rebuilt. Just get it over with, it's not worth it! And have a second person check your torque on every bolt connecting the cam sprocket to the cam itself. If I had someone check, we could've caught my loose bolt and saved ourselves hours and hours of scare.

Sorry to hear you had issues. The only people who don't have issues are people who document their builds on Youtube and conveniently omit the problems.