jdm engines have higher compretion ratios since their higher octane gas prevents detenation, thus preventing engine damage and increasing horsepower. where i live in pa i get 93 octane and when up at school i get 94 octane. i know in japan they have like 100 octane. if i would do a swap, say b18 spec r for instance, would any harm result from the lower octane gas? would the car retard timing to compensate, thus lowering the horsepower to usdm levels, or would it stay at jdm levels? would it even be worth the price of the swap to go from usdm to jdm? high octane isnt a problem, i run 93/94 in my d16z6 anyways, just looking for input, when trying to decide what to swap.