thanks for the reply's peoples. I dont have any battery power at all this morning. So its either the alternator or the battery. My guess is alternator, although i'm charging the battery today to see what happens. Does anyone know the cost and type of alternator i should be looking for??
PS- i checked out the lexus soarer club site, and people there said their new soarer's have had similar probs with their alternator. The light comes on as well as the cat light. They reckon the cat light only comes on in 'sympathy' to the alternator. i'll let you know how it goes.