Kim
From the sound of it you are physically capable of handling yourself from a fitness and surface swimming ability, be happy with that. What do you want from DIR-f? I have not taken the course but from all acounts it is demanding, however that does not mean it is the only way to further your diving skills. Whilst GUE claim that all thier instructors are of a certain level (and based upon their size its probably true), both IANTD and TDI (even PADI) have GOOD instructors as well that will put you through similar skill training and exercises to acheive the same end result. Find a good instructor and work with them (not easy in Japan i know).
From the sound of it you are physically capable of handling yourself from a fitness and surface swimming ability, be happy with that. What do you want from DIR-f? I have not taken the course but from all acounts it is demanding, however that does not mean it is the only way to further your diving skills. Whilst GUE claim that all thier instructors are of a certain level (and based upon their size its probably true), both IANTD and TDI (even PADI) have GOOD instructors as well that will put you through similar skill training and exercises to acheive the same end result. Find a good instructor and work with them (not easy in Japan i know).