In the dubbed cartoon network version, the scene where Ryoko was discovered in Tenchi's bed was shortened because part of her cleavage was shown and Tenchi was reacting to it in a funny way and Ryoko's cleavage was covered with a drawn-on brassier; in the scene where Ryoko was taking a bath, she was naked but ended up with a drawn-on swim suit; the same goes with Ayeka when Ryoko removed her towel in front of Tenchi.
The dubbed version aired on Cartoon Network in 2000 replaced various references to sake with tea, though not all occurances were changed. The dubbed version for sale on video keeps all references to sake.
The dubbed version aired on Cartoon Network in 2000 cut down a frame in the last episode of the series. It it Nagi shows a bartender a photo of Ryoko, which you see very briefly. In it Ryoko is actually showing her middle finger, which explains why the scene was cut short.
The bathhouse episode (featuring the previously mentioned Ayeka-without-a-swimsuit scene) was aired on Cartoon Network in the 'clean' form, with pasted-on swimsuits, none of the slapfighting between Ayeka and Ryoko (along with a brief moment where Ryoko lifts her hair, revealing her breasts, sans nipples, followed immediately Ayeka clobbering her), and redubbed dialogue. This redub mangles the captioning track--garbage appears all throughout it. However, it is still legible enough to pick up the original dialogue (Ryoko's line about "seeing you in your birthday suit", for instance), leaving anyone relying on captions likely confused.