compatible tires ????

Hi, I have a Kia Picanto where in technical record comes to me with some wheels of 155/70 r13 75t, it brings mounted from the house and approved in the technical tab about 165/60 R14 75h, these last are difficult to get cheap, but they have told me that I can put some compatible measures, what are cheaper is true? I will not have problems in the ITV? Which could put them thanks.