The elephant in the room is are you the first and sole owner of the engine from the jump... ??
-- if not, the previous owner could have dogged out the engine & did a poor job maintaining oil levels, how often they changed the oil, may have run a cheaper oil not made for performance driving, etc... I have seen people run kpro & bolt-ons, then part-it out and go back to stock completely fooling the next buyer with a clapped out engine.
My suggestion before boosting your engine, I would run a compression test, next set the engine to T.D.C.. Remove the valvecover and inspect the cam gears & timing chain to see how far off the timing is. If it is off in the slightest do step B below, after A
Since you do not have oil squirters, You need to make sure the oil pump is working correctly. The K20a3 crankshaft is not as good as the A/A2/Z1/Z3. The K20a3's connection rods are thinner and has a thinner rod bearing. Any kind of oiling issue will target the connection rod's at the bearing site connecting @ the crankshaft journals. Engines that are driven hard will weaken at the most important connection points. Honestly,
A: I would pull the cylinder head and install a new head gasket with ARP head-studs.
B: I would install a new oil pump, new oil chain, new oil chain tensioner, new timing chain tensioner, and new timing chain (replace the guides as well).
C: Service Valve Lash, new spark plug seals, new valvecover gasket, install all exhaust studs fort extra strength needed for turbo manifold & turbo weight (try to install a support brace for the ex. manifold)