I've looked into it a bit more and I think I will go with spartan level 3 plus steel with the full spall protection coating. What's your opinion on side plates? I can't decide if they'd be worth the added cost.

Side plates will add a decent amount of protection in the real world, you can't be guaranteed to being squared up to the threat or that there is only a single threat. Did you opt for the steel plates based on cost or durability over ceramic. Armor is one of those things that you will in all likelihood never need but if you do you will need it very badly. Also, what kind of helmet are you going with? Also, I assume that you have your NV and thermal lined out as to how it will interact with the rest of your gear.

I leaning towards steel mainly because of the price. My primary purpose for wanting a setup is because I (a highschooler) am/was very unimpressed with how school admin and police handled a credible threat, in addition to them covering up two separate incidents of students plotting to choot up the school. I'd like to have something that would stay in the truck in case of emergency that would allow me to get away on foot, or if necessary render aid. I watched what happened down in Texas a couple years back, how police waited around outside and it absolutely ticks me off and makes me wonder how I personally can prepare to defend myself and my classmates, should something happen and police drop the ball.