It is my opinion that there is no difference in the usdm and jdm motors. the 10 hp difference in rating most likely comes from emisions stuff on the us motor such as a cat and intake silencers. If you are going to build up the motor it will not matter which one you start with you are going to replace the intake tubing and if you run a test pipe on the usdm motor or add a cat to the jdm one to be legal here you will negate the difference. but its your money do what you want.

unreliable in what way? Ive never heard that its unreliable.