l was doing some research on the lexus GS and they were saying that the base models have leather interior, and the more expensive models have premium leather. Can you please tell me what is the difference.

The more expensive models appear to have semi-analine leather. This type of leather gives up a little in the durability department for a softer hand (softer feeling). They also may be perforated as well (breathe a little better).

The difference is the semi aniline interior mentioned by the former answerer. Semi aniline leather is a type of dying process in which the dye is bled through the leather. This gives it a more consistent color & make it a a bit tougher than the normal leather. Its ''Semi'' because it doesnt use too much die. That way the leather still looks natural yet has the characteristics mention above. However even so the leather on a lexus is somewhat thin, or to put it in a good way, ''soft.'' After use the leather get some considerable wear. It gets wrinkles & scars when equipped with the semi aniline leather (i know because i've got a lexus ls with it). Even so, the leather feels much better than those in many other car brands. Its just simply softer. l would recommend getting the semi aniline only if u r going to be careful with the seats.