There are no major problems to be concerned about, the iLoad is generally sound, but the vehicle you are thinking of buying has done 200,000 km in three years. That would suggest it has been used as a delivery vehicle, so look closely at its history and the possibility that it has had a hard life. Before doing anything make sure it has been regularly serviced. Given regular servicing there is no reason the iLoad won’t do 400,000 km.

You took a share of the responsibility when you went to a clutch place and had a non-factory clutch and flywheel fitted. By doing that you opened the door for Hyundai to walk away from the problem. Had the dealer done the work they might well have found the gearbox problem and could possibly have fixed it under warranty. The only thing you can now do is to go to Hyundai and request goodwill assistance to fix the gearbox problem.