After doing 4 track days with my Sidi Performer Air Boots, I found myself wanting more protection on the track. I decided to get race boots and not use street boot for my next track days. I am a 12 USA normal size (not wide) and went with the 48/13 after reading many reviews. The features and quality are impressive. Very comfortable out of the box. The fact that you can replace everything on this boot, makes it an long lasting boot. The buckle system is very secure and you can customize it for whatever pants you ride with. Have not tested them yet for air flow, but doubt they will disappoint me. I tried the Astars SMX-6 V2 vented, but was never able to get a good size fit. I can say, having had now tried on back to back and evaluated the quality, fit and feel, protection level and comfort, these are it. Yes, they are $80 dollars more expensive. but you know where it went on the boot.