Take your time with the oil pump install. It can get very messy really quickly unless you take your time. Also, you should use Toyota FIPG for it
Make sure you torque the header onto the engine gradually and in a crisscross type pattern. Do not over-torque the nuts either. I think the torque value is 25ish ft-lbs? It may not seem like much, but it's enough. You may also want to use stud lock nuts so they don't back off. I would also suggest re-torquing the header nuts a few times after you've run the car and heated everything up.
I bought a rivnut tool specifically for the intercooler install but found out it wasn't big enough when it came time to use it. I ended up using the DIY bolt/nut/washer method. There's lots of info on Youtube that explains how to do it.
Aside from that, everything else is pretty straight forward.