Basic differences are as follows (These are discussed extensivly in some other threads. Please use search engine)
ES 1 - Japaneese domestic model. 1.5 Lt . DOHC machine ,EPS, Mostly fabric interior. Front grill is not same as ES 5 and ES 8 in face lifted versions(after end of 2003).
ES 5 - Exported to Singapore in south east region basically. 1.6 Lt, Hydrolic power steering, VTi machine, Leather interior(Artificial). Fender strip right around door panels.
ES 8 - Sri Lanka brand new version, 1.5 Lt, DOHC machine. Outer appearence is same as ES5 .
Better if you could buy a ES5 because Steering rack will last more than other two models with out giving rattling noise due to hydrolic machanism and good overall performance.(Face lifted version is the best)
Price varies from 2.7 million- 3.4 million.