Seeing as how you're newer on this forum, @gtman is probably one of the people on this forum that most people here trust his opinion. He's trying to do you a favor since the Injen intakes are known to cause issues. And it doesn't matter with the intake if its an Si or not with the 1.5T, if you...
When I had my 10th Gen Civic, I experimented a lot with different LED bulbs and HID kits. If you want the best, a projector retro fit would be the way to go. There are a few threads about it on the forum, I linked one below. If modifying your stock headlights isnt your thing one of the best LED...
I'll usually use either Zerex or Peak, have had zero issues with either one. I recently used Peak when I drained my coolant to change out my thermostat and radiator hoses.
With the cost of needing to probably convert your CVT to a manual since a sequential transmission I believe are only upgrades for manual transmissions, and then the cost of a sequential transmission itself which can be anywhere from $10K - $20K, it would probably cheaper just to buy another car.
They normally come with the full set when you buy them from Honda.
https://www.collegehillshonda.com/2016-2020-honda-civic-coupe-accessories/08P00-TBJ-100.html
They at least should've disconnected the battery. Disconnecting the battery will cause a bunch of codes to pop up and the car will need to recalibrate itself. Should go away on its own after driving for awhile, if they're still there, try turning the car off then on again. If its still there...
Yeah, I knew about supplying a crankshaft for the short block you purchase from them so they can balance it. Good to know about supplying them with a block if I ever build out a motor.
Yup, I had the Mishimoto intake on my EXL, was pretty much a small oven for the filter element with it being in a metal box, there was no port at the bottom or anything that would bring in any fresh air so IAT were a little on the higher side. Only real plus side to it was the CARB EO sticker...