Comparing 275/30 vs 275/35: the sorter sidewall will yield better acceleration due to the increased gearing effect (smaller diameter). It will be lighter, so less unsprung mass (better reaction to changes in load) and less inertia (better acceleration and braking). The shorter sidewall will also make the tire stiffer, which will make the tire react faster to inputs (steering, brake, throttle) but may also make the tire less compliant to adhere to road surface imperfections.
An important element to consider is that changing the front to rear tire diameter ratio will impact the DSC calculation. For instance, if you reduce the rear diameter compared to the front, the traction control will intervene more often. Due to the smaller size of the rear tires, the DSC is tricked into thinking that the rear tires are spinning faster than they actually are.