ah yes, you have selected the right parts to stock as they will fail when you least expect it!...
I find CAS to be pretty reliable.
It is the TPS / Stepper and Alternator that will fail over time.
For the alternator, i find genunie is best, the voltage tends to be more consistent. I've heat sheilded mine to increase the life.
he 4g63 dump pipe location is not ideal for this. Have you relocated your alternator to the rear of the block since you done have air con? this will significantly increase life and also allow a larger dump pipe to be made...