I haven't had any issues and I run track events fairly often. The biggest issue that cause fade is the heat. Brake fluid can make a big difference when switching from dot3 to 4 or 5 as boiling from the heat will cause tremendous fade/soft pedal. pads that designed for hotter environments I.E. racing, will perform much better as their material composition performs better at high ambient temps. 350 calipers contain more mass, so more resistant to heat. they use a larger pad that covers more of the rotor so you have better heat dissipation. So yes the 350 caliper is better, but I feel like you may have other underlying problems. Is adequate airflow getting up to the rotors? Fluid and pads appropriate for what you are doing?
