How much boost are you running?
The K14 probably won't last all that long at 20PSI. Do you have an EGT gauge?
IMO a good upgrade for you would be a T3 due to the same exhaust mani flange... you would however have to fab/modify the oil return line for the T3.i've been running a T3 on my AAZ for well over 60000 km @ 25+ psi with no problems at all.