Caught this thread late but honestly if you are hitting the track next month you gotta look at your suspension. More power is basically useless if you cant turn or keep the car stable. Since you are on a budget and the ECU is acting up, i would suggest chilling on the engine mods for a minute. Look into the Eibach Pro-Kit Lowering Springs 28102.140 to keep the weight from shifting too much in corners. Be careful with stock tires tho... they wont handle track heat well. Might want to consider the Continental ExtremeContact DWS06 Plus 245/45ZR20 for better grip. For those codes, check out LXForums or the Scat Pack forums. Those guys have documented every sensor mismatch known to man with the manifold swap. Finding a DIY fix there is way cheaper than a shop. Make sure to double check your vacuum lines first. People always overlook the simple stuff when theyre stressed.

Yeah, I have to agree with the previous post about checking the SRV wiring. Those Scat Pack manifolds are a great swap but the 5.7 ECU doesnt always play nice with the active runners if the harness is off or if you dont have a tune to tell the car when to open them. It basically causes a vacuum mess or sensor errors every time tho. If you have $1500 left, you gotta stop buying hard parts and focus on the brains and the reliability before the track day. Its kinda risky to keep pushing it when the ECU is already acting up...

• You definitely need a way to talk to the car. Look into the Diablosport Modified PCM and T2 Platinum Tuner Kit because that 2018 PCM is locked down tight. Itll eat about half your budget but you cant fix the manifold issues without it.
• Heat management is next. Heavy cars like the 300S soak up heat fast. A Mishimoto 180 Degree Racing Thermostat is a cheap way to keep things stable.
• For the track, dont forget the oil. A Billet Technology Signature Series Catch Can 5.7L Hemi keeps the gunk out of your new manifold.
• Since your stock pads will fade in two laps, grab PowerStop Z26 Street Warrior Brake Pads to handle the heat better. Stay focused on the tune first. If the ECU is unhappy, the car is gonna pull timing and youll actually be slower than stock despite the new manifold. Its all about getting the electronics to agree with the mechanical stuff.

Oh man, i totally feel that stress! I remember when I first started modding my 300, i was so hyped to get every ounce of power out of it that i almost ruined the whole engine. Seriously, it was a nightmare!! I ended up throwing a bunch of parts at it way too fast without thinking about the basics, and one day on a hot summer drive, the whole thing just started smoking because I hadn't properly handled the heat management. It was terrifying!! After that scare, I did a massive 180 and focused strictly on making sure the car could actually handle the stress I was putting on it. I spent a good chunk of my budget basically just making sure the fluids stayed cool and the suspension was actually tight enough to keep me on the road. Best decision i ever made! These cars are heavy, so when you start pushing them on a track, things get hot and loose real fast. The peace of mind knowing the car wont explode when I'm pushing it is honestly better than an extra 10 horsepower. I love it when a build feels solid and planted. Nowadays, I always tell people to look at the cooling system first. I got a much bigger radiator and a better oil cooler setup before I touched anything else on my current car. It makes a world of difference when you're out there for a long session and your temps stay rock steady. It's not the 'cool' way to spend money, but man, it feels fantastic to drive home after a track day instead of calling a tow truck!! Seriously, focusing on that reliability side changed everything for me and made me a much more confident driver.