Arouse the DAMPFHAMMER!
Hi Gabe, I am building a NA'd 86.5x86 engine (K20A2 basis), aming for 250+ whp. Building means here: costume parts for IM, H, coolant and oil circuit and cylinder head (port and valve seat design), further forged crank assembly parts, lightened flywheel and so on....k24 being the best for al motor build and the k20 for a turbo build...
The same or higher peak power you can reach with an NA setup combination of K24 block/K20 head combination, adequat cams, CAI, RRC IM, H, E at a just better torque curve and a 10th of cost.
The double and even higher of that you can reach with just a TC'd stock longblock (K20 or K24) and an adapted exhaust and intake (stock IM)...lowest cost per power ratio if tuning is of highest quality, which is a duty allways and here especially .
I still don't know what you are aiming for...but if you want to boost it, take the K20Z3/Z4/A2/A of your friend mount a turbo charger kit on it and go to tune it (adaption of chassis, tyres, brakes, ... = duty). That's the easiest way...
Concerning the type K20A/A2/Z1/Z3/Z4, these are all iVTEC engines of CR's ≥ 11.0:1 and of around stock 200 flwhp and a perfect basis for everything. All others like the K20A3 have limitations like reduced head flow performance and efficiency trimmed valvetrain, which maybe are still good within a TC setup but not worth the money for NA engine setups. There exists a massive amount of information here at K20a.org to this...