What sort of engine oil should I use for a 1996 toyota celica which has done 205,640kms ?

128,000 miles for your car is barely half way to what you can expect to get from it. I suggest a good synthetic, maybe 5/30, 10/30. and do not use additives. Modern synthetics have everything they need already in them. Mobil1, Pennzoil Platinum, Castrol Edge, Amsoil

Thank you ! much appreciated.

You're welcome. Remember these oils cost a lot more but will save you in the long haul. They last longer. lubricate better, hold up to temperature extremes better, and more