Firstly , 195 70 R15 is a huge tire. I have no idea whether you can even fit it on the Punto. It fits the needs and performance requirements of load carriers and people movers etc rather than that of a car like the Punto. Secondly, the only effect an upsized tire will have on performance is that it will marginally increase the acceleration times ; because upsized tires increase the effective gear ratios, that is , make them a bit higher. So , enjoy the Punto as it is. If you're really serious about increasing GC , then a change in the suspension set up is the best way out. Good luck. Gurjinder.