You can play with JP text on the NTSC-U and PAL versions, but it's negligible differences to my knowledge. Just change the language in the options :) And I can't say for model, I've used a 90k and a 70k PS2 and had no issues with either. But haven't researched if one was faster.

Mostly models tend to affect PSX titles more than PS2. I'd recommend a slim, mind.