From the picture below, you can see the difference of the Beta75pro frame of different versions.
Please note that the OG 75pro frame doesn't fit 0703 19000KV motors.
Here are the IMPROVEMENTS we've made.
Really not recommend the 0703 motors with a 65mm frame ( like Beta65 Pro frame or BWhoop B06 etc). Why? The combo of 0703 motors and 31mm props (for 65mm frame) has a really low efficiency. Really not power enough. For the 65mm 1S brushless drone, recommend the 0603 motors (comming soon).
Here is the testing result of different motors and frames combo.