Contrary to my earlier comments about the Mk1 and Mk2 not being much different, I have noticed several other differences.
Heater controls slightly different. Steering wheel different. Grille different. Electric window switches in door armrests in Mk2, in cenre console in Mk1. Mk2 GSL has digital clock in the fake wood strip in the higher part of the dash. SL retains same analogue clock as Mk1 GSL. Dashboard instrument pod completely different and with different guages inside. Seat material different. Gearstick and centre console different. Cigar lighter in a different position. Indicator and wiper stalks may be different. Radio different. The Mk2 GSL actually had a very nice auto-reverse tape deck made by Hyundai electronics themselves.