ok mate.. remember these words before you read anything else - most on here drive manuals nad have never driven an auto skyline.. thus, they only have a preconceived idea that automatic skylines are shit without having driven one. obviously you know that's not the case, so be wary of what advice you wish to take as some posts will be opinions, while others will be opinions based on the fact that they drive/own an automatic skyline
having said that, i drive an automatic r32, which has a similar (if not the same) gearbox to the r33
troubles i have had in the last 3.5 years? none
how does it shift gears? it can flare on some gear changes but that also depends on the gearbox condition. it drives well for me and changes great 99% of the time
its like anything mechanical - it will last a long and happy life if you service it properly (every 20,000kms) and use it as it were intended
oh, btw, i have a transmission cooler attached to mine, and i believe it was a worthy investment at less than $100 from supercheap
i have read of people running over 200rwkw in rb25 automatics without a hitch i personally run 155rwkw through my rb20 auto and it loves it
good luck with the conversion,
Warren.