Best bang for the buck - so cheapest you can get by with? Stay away from $2k quality sets from ARH, Kooks, TTi and Belanger then. Regardless of whatever long tubes you eventually get, real performance gains won't be had until you get a custom tune for it.
Install is a PITA on jackstands and your back but doable. Plan on it taking a full workday. Loosening the engine mounts definitely helps with the additional 3-5" lift it gives you. Protect the O2 sensors and put back in same relative location (e.g. driver rear). If you break an O2 extension Caspers Electronics sells them under $25. Driver's side ain't too bad because the coolant reservoir and air filter areas give you room to maneuver. The passenger side however is a wall and you have the dipstick to contend with too.
Another option builders/mechanics seem to use is pulling the actual heads and installing the headers on the work bench. Oh, the SRT header bolts are cheap and come with a thread locker already applied. And consensus is to only use the OEM Mopar gasket.
Picking out what long tube headers I want to go with from Stainless Works with catted mid pipes. Going to be staying NA, probably with a cam. I have a 3" aftermarket exhaust already. Which primary diameter should I get?
Does anyone know the part numbers to add the hellcat lower air box and headlight air catcher tube to a 2020 Challenger Scat Pack W/B and if so can I use the upper air box cover that comes with the car ??