Almost right almost wrong, bu theres 3 ppl now with 200whp+ KAs… and no its not cheap or for just anybody.
There’s also 300whp+ SOHC KAs that can be built but those most definetely are race only.
Realistically most people push between 150-190whp with nothing too fancy.
As was mentioned intake, exhaust+testpipe (contrary to popular belief KA likes 3.0 its just loud as shit), 4-2-1 headers (definetely make a dif too but extra noise), underdrive crank pulley, advancing timing and running higher octane
They are all small bits… but add up, however the price adds up too, so unless you’re really into spending money for something for yourself thats different or with a different goal dont expect alot of power.
The KA is very rich… so tuning is a definite way to make extra power… nistune is what im looking for… a shop locally tunes it and can get it… not expensive all being said and done… Imho its the most $/hp cost effective considering the above mods cost almost as much and not as much gains.
Its the all around effect that gains u most power.
In regards to higher compression pistons/etc… surprisingly it doesnt do much for the KA… unless u change around everything…
A fully counter weighed crank would be beneficial in a build like this and revving past 8k (been done…) but now you see how expensive shit really gets.
More than 190whp is just wanting to rape your wallet.
Turbo is the way, or as most of son240 will tell u, sr20det is the way 
I like my NA KA, but just for now 