Which plug should I use? Anything I'm missing?
 

Getting the ix back together, transmission and clutch replacement.
Going to get the evo tuned after put back together and break in.

Setup :

Fp Black
built shep trans
built tcase
bosch 1600 cc injectors
aero 340
bfmic
hard pipes
exhaust
intake
act monoloc
fpr with lines
works sts

Currently running the ikh24 one step colder plug when I was just bolt ons and wasn't sure if I should stay with them.

Also if anyone has any other parts I should look into that slipped my mind I would appreciate it.

Wideband?
Boost controller?

ask your tuner

also, NGK ILFR7H

there's no reason not to run the stock plugs unless you have good reason not to. thinking that one step colder plugs are needed "just because" is not good reason

Stock heat range plugs are good to about 700-800whp.